Database

Each origin has an associated set of databases. A database comprises one or more object stores which hold the data stored in the database.

Every database has a name which identifies it within a specific origin. The name can be any string value, including the empty string, and stays constant for the lifetime of the database. Each database also has a current version. When a database is first created, its version is 0.

Implementations MUST support all names. If an implementation uses a storage mechanism which can't handle arbitrary database names, the implementation must use an escaping mechanism or something similar to map the provided name to a name that it can handle.

Each database has one version at a time; a database can't exist in multiple versions at once. The only way to change the version is using a "versionchange" transaction.

Databases has a delete pending flag which is used during deletion. When a database is requested to be deleted the flag is set to true and all attempts at opening the database are stalled until the database can be deleted.

The act of opening a database creates a connection. There MAY be multiple connections to a given database at any given time. Each connection has a closePending flag which initially is set to false.

When a connection is initially created it is in opened state. The connection can be closed through several means. If the connection is GCed or execution context where the connection is created is destroyed (for example due to the user navigating away from that page), the connection is closed. The connection can also be closed explicitly using the steps for closing a database connection. When the connection is closed the closePending flag is always set to true if it hasn't already been.

The IDBDatabase and IDBDatabaseSync interfaces represent a connection to a database.

Object Store

An object store is the primary storage mechanism for storing data in a database.

Each database contain a set of object stores. The set of object stores can be changed, but can only be changed using a "versionchange" transactions, i.e. in response to a upgradeneeded event. When a new database is created it doesn't contain any object stores.

The object store has a list of records which hold the data stored in the object store. Each record consists of a key and a value. The list is sorted according to key in ascending order. There can never be multiple records in a given object store with the same key.

Every object store has a name. The name is unique within the database to which it belongs. Every object store also optionally has a key generator and an optional key path. If the object store has a key path it is said to use in-line keys. Otherwise it is said to use out-of-line keys.

The object store can derive the key from one of three sources:

1. A key generator. A key generator generates a monotonically increasing numbers every time a key is needed.
2. Keys can be derived via a key path.
3. Keys can also be explicitly specified when a value is stored in the object store.

The IDBObjectStore and IDBObjectStoreSync interfaces represent an object store. Note however that multiple instances of those interfaces representing the same object store can exist.

Keys

In order to efficiently retrieve records stored in an indexed database, each record is organized according to its key. A value is said to be a valid key if it is one of the following types: Array JavaScript objects [[!ECMA-262]], DOMString [[!WEBIDL]], Date [[!ECMA-262]] or float [[!WEBIDL]]. However Arrays are only valid keys if every item in the array is defined and is a valid key (i.e. sparse arrays can not be valid keys) and if the Array doesn't directly or indirectly contain itself. Any non-numeric properties are ignored, and thus does not affect whether the Array is a valid key. Additionally, if the value is of type float, it is only a valid key if it is not NaN, and if the value is of type Date it is only a valid key if its [[PrimitiveValue]] internal property, as defined by [[!ECMA-262]], is not NaN. Conforming user agents MUST support all valid keys as keys.

Infinite float values are valid keys. As are empty Arrays.

For purposes of comparison, all Arrays are greater than all DOMString, Date and float values; all DOMString values are greater than all Date and float values; and all Date values are greater than all float values. Values of type float are compared to other float values numerically. Values of type Date are compared to other Date values chronologically. Values of type DOMString are compared to other values of type DOMString by using the algorithm defined by step 4 of section 11.8.5, The Abstract Relational Comparison Algorithm, of the ECMAScript Language Specification [[!ECMA-262]]. Values of type Array are compared to other values of type Array as follows:

1. Let A be the first Array value and B be the second Array value.
2. Let length be the lesser of A's length and B's length.
3. Let i be 0.
4. If the ith value of A is less than the ith value of B, then A is less than B. Skip the remaining steps.
5. If the ith value of A is greater than the ith value of B, then A is greater than B. Skip the remaining steps.
6. Increase i by 1.
7. If i is not equal to length, go back to step 4. Otherwise continue to next step.
8. If A's length is less than B's length, then A is less than B. If A's length is greater than B's length, then A is greater than B. Otherwise A and B are equal.

Note that Arrays that contain other Arrays are allowed as valid keys. In this case the algorithm above runs recursively when comparing the individual values in the arrays.

As a result of the above rules, negative infinity is the lowest possible value for a key. There is no highest possible key value. This is because an array of any candidate highest key followed by another valid key is even higher.

The terms greater than, less than and equal to is defined in the terms of the above comparisons.

The following examples illustrate the different behaviors when trying to use in-line keys and key generators to save an object to an object store.

Values

Each record is associated with a value. Conforming user agents MUST support any value supported by the structured clone algorithm [[!HTML5]]. This includes simple types such as DOMString and Date as well as Object and Array instances.

Key Path

A key path is a DOMString or Array that defines how to extract a key from a value. A valid key path is one of:

• An empty DOMString.
• A DOMString containing a JavaScript identifier [[!ECMA-262]].
• A DOMString containing multiple Javascript identifiers separated by periods (ASCII character code 46) [[!ECMA-262]].
• A non-empty Array containing only DOMStrings conforming to the above requirements.

Note that spaces are not allowed within a key path. To evaluate a key path, run the steps for extracting a key from a value using a key path.

Key path values can only be accessed from properties explicitly copied by the structured clone algorithm, as well as the following properties:

• Blob.size
• Blob.type
• File.name
• File.lastModifiedDate
• Array.length
• String.length

Index

It is sometimes useful to retrieve records in an object store through other means than their key. An index allows looking up records in an object store using properties of the values in the object stores records.

An index is a specialized persistent key-value storage and has a referenced object store. The index has a list of records which hold the data stored in the index. The records in an index are automatically populated whenever records in the referenced object store are inserted, updated or deleted. There can be several indexes referencing the same object store, in which changes to the object store cause all such indexes to get updated.

The values in the index's records are always values of keys in the index's referenced object store. The keys are derived from the referenced object store's values using a key path. If a given record with key X in the object store referenced by the index has the value A, and evaluating the index's key path on A yields the result Y, then the index will contain a record with key Y and value X.

Records in an index are said to have a referenced value. This is the value of the record in the index's referenced object store which has a key equal to the index's record's value. So in the example above, the record in the index whose key is Y and value is X has a referenced value of A.

Each record in an index reference one and only one record in the index's referenced object store. However there can be multiple records in an index which reference the same record in the object store. And there can also be no records in an index which reference a given record in an object store.

The records in an index are always sorted according to the records key. However unlike object stores, a given index can contain multiple records with the same key. Such records are additionally sorted according to the records value.

An index contains a unique flag. When this flag is set to true, the index enforces that no two records in the index has the same key. If a record in the index's referenced object store is attempted to be inserted or modified such that evaluating the index's key path on the records new value yields a result which already exists in the index, then the attempted modification to the object store fails.

An index also contains a multiEntry flag. This flag affects how the index behaves when the result of evaluating the index's key path yields an Array. If the multiEntry flag is false, then a single record whose key is an Array is added to the index. If the multiEntry flag is true, then the one record is added to the index for each item in the Array. The key for each record is the value of respective item in the Array.

The IDBIndex and IDBIndexSync interfaces provide access to the metadata of an index. Note however that multiple instances of those interfaces representing the same index can exist.

Transaction

A transaction is used to interact with the data in a database. Whenever data is read or written to the database it is done by using a transaction.

All transactions are created through a connection, which is the transaction's connection. The transaction has a mode that determines which types of interactions can be performed upon that transaction. The mode is set when the transaction is created and remains fixed for the life of the transaction. The transaction also has a scope that determines the object stores with which the transaction may interact. Transactions have an active flag, which determines if new requests can be made against the transaction. Finally, transactions also contain a request list of requests which have been made against the transaction.

Each transaction has a fixed scope, determined when the transaction is created. A transaction's scope remains fixed for the lifetime of that transaction.

Transactions offer some protection from application and system failures. A transaction may be used to store multiple data records or to conditionally modify certain data records. A transaction represents an atomic and durable set of data access and data mutation operations.

Transactions are expected to be short lived. This is encouraged by the automatic committing functionality described below. Authors can still cause transactions to run for a long time; however, this usage pattern is not generally recommended as it can lead to a bad user experience.

The lifetime of a transaction is as follows:

1. A transaction is created using IDBDatabase.transaction. The arguments passed determine the scope of the transaction and whether the transaction is read-only. When a transaction is created its active flag is initially set to true.
2. The implementation MUST allow requests to be placed against the transaction whenever the active flag is true. This is the case even if the transaction has not yet been started. Until the transaction is started the implementation MUST NOT execute these requests; however, the implementation MUST keep track of the requests and their order. Requests may be placed against a transaction only while that transaction is active. If an attempt is made to place a request against a transaction when that transaction is not active, the implementation MUST reject the attempt by throwing a DOMException of type TransactionInactiveError.
3. Once an implementation is able to enforce the constraints defined for the transaction mode, defined below, the implementation MUST queue up an operation to start the transaction asynchronously. The timing for when this happens is affected by:
   • The mode in which the transaction is opened.
   • Which object stores are included in the scope of the transaction.
4. Once the transaction has been started the implementation can start executing the requests placed against the transaction. Unless otherwise defined, requests MUST be executed in the order in which they were made against the transaction. Likewise, their results MUST be returned in the order the requests were placed against a specific transaction. There is no guarantee about the order that results from requests in different transactions are returned. Similarly, the transaction modes ensure that two requests placed against different transactions can execute in any order without affecting what resulting data is stored in the database.
5. A transaction can be aborted at any time before it is finished, even if the transaction isn't currently active or hasn't yet started. When a transaction is aborted the implementation MUST undo (roll back) any changes that were made to the database during that transaction. This includes both changes to the contents of object stores as well as additions and removals of object stores and indexes.
6. A transaction can fail for reasons not tied to a particular DOMRequest. For example due to IO errors when committing the transaction, or due to running into a quota limit where the implementation can't tie exceeding the quota to a partcular request. In this case the implementation MUST run the steps for aborting a transaction using the transaction as transaction and the appropriate error type as error. For example if quota was exceeded then QuotaExceededError should be used as error, and if an IO error happened, UnknownError should be used as error.
7. When a transaction can no longer become active, the implementation MUST attempt to commit it, as long as the transaction has not been aborted. This usually happens after all requests placed against the transaction have been executed and their returned results handled, and no new requests have been placed against the transaction. When a transaction is committed, the implementation MUST atomically write any changes to the database made by requests placed against the transaction. That is, either all of the changes MUST be written, or if an error occurs, such as a disk write error, the implementation MUST NOT write any of the changes to the database. If such an error occurs, the implementation MUST abort the transaction by following the steps for aborting a transaction, otherwise it MUST commit the transaction by following the steps for committing a transaction.
8. When a transaction is committed or aborted, it is said to be finished. If a transaction can't be finished, for example due to the implementation crashing or the user taking some explicit action to cancel it, the implementation MUST abort the transaction.

Transactions are opened in one of three modes. The mode determines how concurrent access to object stores in the transaction are isolated.

1. "readonly". This mode means that the transaction is only allowed to read data. No modifications can be done by this type of transaction. This has the advantage that several "readonly" transactions can run at the same time even if their scopes are overlapping, i.e. if they are using the same object stores. This type of transaction can be created any time once a database has been opened using the IDBDatabase.transaction() or IDBDatabaseSync.transaction() functions.
2. "readwrite". The type of transaction is allowed to read, modify and delete data from existing object stores. However object stores and indexes can't be added or removed. Multiple "readwrite" transactions can't run at the same time if their scopes are overlapping since that would mean that they can modify each other's data in the middle of the transaction. This type of transaction can be created any time once a database has been opened using the IDBDatabase.transaction() function.
3. "versionchange". This is similar to a "readwrite" transaction, however it can additionally create and remove object stores and indexes. It's the only type of transaction that can do so. This type of transaction can't be manually created, but instead is created automatically when a upgradeneeded event is fired.

The this is defined in more detail below.

Any number of transactions opened in "readonly" mode are allowed to run concurrently, even if the transaction's scope overlap and include the same object stores. As long as a "readonly" transaction is running, the data that the implementation returns through requests created with that transaction MUST remain constant. That is, two requests to read the same piece of data MUST yield the same result both for the case when data is found and the result is that data, and for the case when data is not found and a lack of data is indicated.

There are a number of ways that an implementation ensures this. The implementation can prevent any "readwrite" transaction, whose scope overlaps the scope of the "readonly" transaction, from starting until the "readonly" transaction finishes. Or the implementation can allow the "readonly" transaction to see a snapshot of the contents of the object stores which is taken when the "readonly" transaction started.

Similarly, implementations MUST ensure that a "readwrite" transaction is only affected by changes to object stores that are made using the transaction itself. For example, the implementation MUST ensure that another transaction does not modify the contents of object stores in the "readwrite" transaction's scope. The implementation MUST also ensure that if the "readwrite" transaction completes successfully, the changes written to object stores using the transaction can be committed to the database without merge conflicts. An implementation MUST NOT abort a transaction due to merge conflicts.

If multiple "readwrite" transactions are attempting to access the same object store (i.e. if they have overlapping scope), the transaction that was created first MUST be the transaction which gets access to the object store first. Due to the requirements in the previous paragraph, this also means that it is the only transaction which has access to the object store until the transaction is finished.

Generally speaking, the above requirements mean that "readwrite" transactions which have overlapping scopes always run in the order they were created, and never run in parallel.

A "versionchange" transaction never run concurrently with other transactions. When a database is opened with a version number higher than the current version, a new "versionchange" transaction is automatically created and made available through the "upgradeneeded" event. The "upgradeneeded" event isn't fired, and thus the "versionchange" transaction isn't started, until all other connections to the same database are closed. This ensures that all other transactions are finished.

As long as a "versionchange" transaction is running, attempts to open more connections to the same database are delayed, and any attempts to use the same connection to start additional transactions will result in an exception being thrown. Thus "versionchange" transactions not only ensure that no other transactions are running concurrently, but also ensure that no other transactions are queued against the same database as long as the transaction is running.

"versionchange" transaction is automatically created when a database version number is provided that is greater than the current database version. This transaction will be active inside the onupgradeneeded event handler, allowing the creation of new object stores and indexes.

User agents MUST ensure a reasonable level of fairness across transactions to prevent starvation. For example, if multiple "readonly" transactions are started one after another the implementation MUST NOT indefinitely prevent a pending "readwrite" transaction from starting.

Each transaction object implements either the IDBTransaction or the IDBTransactionSync interface.

Requests

Each reading and writing operation on a database is done using a request. Every request represents one read or write operation. Requests have a done flag which initially is false, and a source object. Every request also has a result and an error attribute, neither of which are accessible until the done flag is set to true.

Finally, requests have a request transaction. When a request is created, it is always placed against a transaction using either the steps for asynchronously executing a request or the steps for synchronously executing a request. The steps set the request transaction to be that transaction. The steps do not set the request transaction to be that request for the request returned from an IDBFactory.open call however. That function create requests which have a null request transaction.

Key Range

Records can be retrieved from object stores and indexes using either keys or key ranges. A key range is a continuous interval over some data type used for keys.

A key range MAY be lower-bounded or upper-bounded (there is a value that is, respectively, smaller than or larger than all its elements). A key range is said to be bounded if it is both lower-bounded and upper-bounded. If a key range is neither lower-bounded nor upper-bounded it is said to be unbounded. A key range MAY be open (the key range does not include its endpoints) or closed (the key range includes its endpoints). A key range MAY consist of a single value.

The IDBKeyRange interface defines a key range.

readonly attribute any lower

This value is the lower-bound of the key range.

readonly attribute any upper

This value is the upper-bound of the key range.

readonly attribute boolean lowerOpen

Returns false if the lower-bound value is included in the key range. Returns true if the lower-bound value is excluded from the key range.

readonly attribute boolean upperOpen

Returns false if the upper-bound value is included in the key range. Returns true if the upper-bound value is excluded from the key range.

IDBKeyRange only()

Creates and returns a new key range with both lower and upper set to value and both lowerOpen and upperOpen set to false.

any value

The only value

DataError

The value parameter was not passed a valid key.

IDBKeyRange lowerBound()

Creates and returns a new key range with lower set to lower, lowerOpen set to open, upper set to undefined and and upperOpen set to true.

any lower

The lower bound value

optional boolean open

Set to false if the lower-bound should be included in the key range. Set to true if the lower-bound value should be excluded from the key range. Defaults to false (lower-bound value is included).

DataError

The value parameter was not passed a valid key.

IDBKeyRange upperBound()

Creates and returns a new key range with lower set to undefined, lowerOpen set to true, upper set to upper and and upperOpen set to open.

any upper

The upper bound value

optional boolean open

Set to false if the upper-bound should be included in the key range. Set to true if the upper-bound value should be excluded from the key range. Defaults to false (upper-bound value is included).

DataError

The value parameter was not passed a valid key.

IDBKeyRange bound()

Creates and returns a new key range with lower set to lower, lowerOpen set to lowerOpen, upper set to upper and upperOpen set to upperOpen.

any lower

The lower-bound value

any upper

The upper-bound value

optional boolean lowerOpen

Set to false if the lower-bound should be included in the key range. Set to true if the lower-bound value should be excluded from the key range. Defaults to false (lower-bound value is included).

optional boolean upperOpen

Set to false if the upper-bound should be included in the key range. Set to true if the upper-bound value should be excluded from the key range. Defaults to false (upper-bound value is included).

DataError

Either the lower or upper parameters were not passed a valid key or the lower key is greater than the upper key or the lower key and upper key match and either of the bounds are open.

A key is in a key range if both the following conditions are fulfilled:

• The key range lower value is undefined or less than key. It may also be equal to key if lowerOpen is false.
• The key range upper value is undefined or greater than key. It may also be equal to key if upperOpen is false.

Cursor

Cursors are a transient mechanism used to iterate over multiple records in a database. Storage operations are performed on the underlying index or an object store.

A cursor comprises a range of records in either an index or an object store. The cursor has a source that indicates which index or object store is associated with the records over which the cursor is iterating. A cursor maintains a position over this series, which moves in a direction that is in either monotonically increasing or decreasing order of the record keys. Cursors also have a key and a value which represent the key and the value of the last iterated record. Cursors finally have a got value flag. When this flag is false, the cursor is either in the process of loading the next value or it has reached the end of its range, when it is true, it indicates that the cursor is currently holding a value and that it is ready to iterate to the next one.

There are four possible values for a cursor's direction. The direction of a cursor determines if the cursor initial position is at the start of its source or at its end. It also determines in which direction the cursor moves when iterated, and if it skips duplicated values when iterating indexes. The allowed values for a cursor's direction is as follows:

• "next". This direction causes the cursor to be opened at the start of the source. When iterated, the cursor should yield all records, including duplicates, in monotonically increasing order of keys.
• "nextunique". This direction causes the cursor to be opened at the start of the source. When iterated, the cursor should not yield records with the same key, but otherwise yield all records, in monotonically increasing order of keys. For every key with duplicate values, only the first record is yielded. When the source is an object store or a unique index, this direction has the exact same behavior as "next".
• "prev". This direction causes the cursor to be opened at the end of the source. When iterated, the cursor should yield all records, including duplicates, in monotonically decreasing order of keys.
• "prevunique". This direction causes the cursor to be opened at the end of the source. When iterated, the cursor should not yield records with the same key, but otherwise yield all records, in monotonically decreasing order of keys. For every key with duplicate values, only the first record is yielded. When the source is an object store or a unique index, this direction has the exact same behavior as "prev".

If the source of a cursor is an object store, the effective object store of the cursor is that object store and the effective key of the cursor is the cursor's position. If the source of a cursor is an index, the effective object store of the cursor is that index's referenced object store and the effective key is the cursor's object store position.

It is possible for the list of records which the cursor is iterating over to change before the full range of the cursor has been iterated. In order to handle this, cursors maintain their position not as an index, but rather as a key of the previously returned record. For a forward iterating cursor, the next time the cursor is asked to iterate to the next record it returns the record with the lowest key greater than the one previously returned. For a backwards iterating cursor, the situation is opposite and it returns the record with the highest key less than the one previously returned.

For cursors iterating indexes the situation is a little bit more complicated since multiple records can have the same key and are therefore also sorted by value. When iterating indexes the cursor also has an object store position, which indicates the value of the previously found record in the index. Both position and the object store position are used when finding the next appropriate record.

Cursor objects implement the IDBCursor or the IDBCursorSync interfaces. There is only ever one IDBCursor or IDBCursorSync instance representing a given cursor. However there is no limit on how many cursors can be used at the same time.

Exceptions

Each of the exceptions defined in the IndexedDB spec is a DOMException with a specific type. [[!DOM4]] Existing DOM Level 4 exceptions will set their code to a legacy value; however, the new indexedDB type exceptions will have a code value of 0. The message value is optional.

IndexedDB uses the following new DOMException types with their various messages. All of these new types will have a code value of 0 zero.

IndexedDB reuses the following existing DOMException types from [[!DOM4]]. These types will continue to return the codes and names as specified in DOM4; however, they will have the following messages when thrown from an IndexedDB API:

Options Object

Options objects are dictionary objects [[!WEBIDL]] which are used to supply optional parameters to some indexedDB functions like createObjectStore and createIndex. The attributes on the object correspond to optional parameters on the function called.

                  
dictionary IDBObjectStoreParameters {
  DOMString? keyPath = null;
  boolean autoIncrement = false;
};
                
              

                
dictionary IDBIndexParameters {
  boolean unique = false;
  boolean multiEntry = false;
};
                
              

                
dictionary IDBVersionChangeEventInit : EventInit {
  unsigned long long oldVersion = 0;
  unsigned long long? newVersion = null;
};
                
              

Key Generators

When a object store is created it can be specified to use a key generator. A key generator keeps an internal current number. The current number is always a positive integer. Whenever the key generator is used to generate a new key, the generator's current number is returned and then incremented to prepare for the next time a new key is needed. Implementations MUST use the following rules for generating numbers when a key generator is used.

• Every object store that uses key generators use a seprate generator. I.e. interacting with one object store never affects the key generator of any other object store.
• The current number of a key generator is always set to 1 when the object store for that key generator is first created.
• When a key generator is used to generate a new key for a object store, the key generator's current number is used as the new key value and then the key generator's current number is increased by 1.

• When a record is stored and an key value is specified in the call to store the record, if the specified key value is a float greater than or equal to the key generator's current number, then the key generator's current number is set to the smallest integer number greater than the explicit key. A key can be specified both for object stores which use in-line keys, by setting the property on the stored value which the object store's key path points to, and for object stores which use out-of-line keys, by passing a key argument to the call to store the record.

  Only specified keys values which are float values affect the current number of the key generator. Dates and Arrays which contain floats do not affect the current number of the key generator. Nor do DOMString values which could be parsed as floats. Likewise, negative float numbers do not affect the current number since they are always lower than the current number.

• Modifying a key generator's current number is considered part of a database operation. This means that if the operation fails and the operation is reverted, the current number is reverted to the value it had before the operation started. This applies both to modifications that happen due to the current number getting increased by 1 when the key generator is used, and to modifications that happen due to
• Likewise, if a transaction is aborted, the current number of the key generator's for all object stores in the transaction's scope is reverted to the values they had before the transaction was started.
• When the current number of a key generator reaches above the value 2^53 (9007199254740992) any attempts to use the key generator to generate a new key will result in an error. It's still possible to insert records into the object store by specifying an explicit key, however the only way to use a key generator again for the object store is to delete the object store and create a new one.

  Note that as long as key generators are used in a normal fashion this will not be a problem. If you generate a new key 1000 times per second day and night, you won't run into this limit for over 285000 years.

• The current number for a key generator never decreases, other than as a result of database operations being reverted. Deleting a record from an object store never affects the object store's key generator. Even clearing all records from an object store, for example using the clear() function, does not affect the current number of the object store's key generator.

A practical result of this is that the first key generated for an object store is always 1 (unless a higher numeric key is inserted first) and the key generated for an object store is always a positive integer higher than the highest numeric key in the store. The same key is never generated twice for the same object store unless a transaction is rolled back.

The IDBRequest Interface

The IDBRequest interface provides means to access results of asynchronous requests to databases and database objects using event handler attributes [[!DOM-LEVEL-3-EVENTS]].

readonly attribute any result

When the done flag is true, getting this property MUST return the result of the request. This is undefined when the request resulted in an error. When the done flag is false, getting this property MUST throw a DOMException of type InvalidStateError.

InvalidStateError

Thrown when this attribute was read when the done flag was set to false.

readonly attribute DOMError error

When the done flag is true, getting this property MUST return the error of the request. This is null when no error occurred. When the done flag is false, getting this property MUST throw a DOMException of type InvalidStateError.

InvalidStateError

Thrown when this attribute was read when the done flag was set to false.

readonly attribute object source

Getting this property MUST return the source for the request. Returns null when there is no source set.

readonly attribute IDBTransaction transaction

Getting this property MUST return the transaction for the request. This property can be null for certain requests, such as for request returned from IDBFactory.open.

readonly attribute enum readyState

When the done flag is false, returns "pending", otherwise returns "done".

[TreatNonCallableAsNull] attribute Function? onsuccess

The event handler for the success event

[TreatNonCallableAsNull] attribute Function? onerror

The event handler for the error event

When a request is made, a new request is returned with its readyState set to "pending". If a request completes successfully, the readyState is changed to "done", the result is set to the result of the request, and an event with type success is fired at the request.

If an error occurs while performing the operation, the readyState is changed to "done", the error attribute is set to a DOMError type that matches the error, and an event with type error is fired at the request.

The open and deleteDatabase functions on IDBFactory uses a separate interface for its requests in order to make use of the upgradeneeded event easier.

[TreatNonCallableAsNull] attribute Function? onupgradeneeded

The event handler for the upgradeneeded event

The task source for these tasks is the database access task source.

Event interfaces

This specification fires events with the following custom interfaces:

readonly attribute unsigned long long oldVersion

Returns the old version of the database.

readonly attribute unsigned long long? newVersion

Returns the new version of the database. See the steps for running a "versionchange" transaction.

Events are constructed as defined in Constructing events, in [[!DOM4]].

Opening a database

Window and WorkerUtils objects MUST implement the IDBEnvironment interface.

readonly attribute IDBFactory indexedDB

This attribute provides applications a mechanism for accessing capabilities of indexed databases.

Every method for making asynchronous requests returns an IDBRequest object that communicates back to the requesting application through events. This design means that any number of requests can be active on any database or object handle at a time.

IDBOpenDBRequest open()

When invoked, this method MUST create a request and return it. The created request MUST implement the IDBOpenDBRequest interface and have its source set to null. The method then queues up an operation to run the steps for opening a database. Let origin be the origin of the IDBEnvironment used to access this IDBFactory, name and version be the name and version parameters passed to this function, and request be the newly created request.

If no version is specified and a database exists, use the current database version and follow the steps for opening a database. If no version is specified and no database exists, set database version to 1, follow the steps for opening a database, and return a database without object stores.

If an error is returned from the steps above, the implementation MUST set the error attribute of the request to a DOMError whose name is the same as the error returned, and dispatch an event at the request. The event must use the Event interface and have its type set to "error". The event does bubble but is not cancelable. The propagation path of the event is just the request.

If the steps above are successful, the implementation MUST set the result to the connection created by the steps above and dispatch an event at request. The event must use the Event interface and have its type set to "success". The event does not bubble and is not cancelable. The propagation path of the event is just the request. If the steps above resulted in a "versionchange" transaction being run, then firing the "success" event MUST be done after the “versionchange” transaction completes.

The last requirement is to ensure that in case another version upgrade is about to happen, the success event is fired on the connection first so that the page gets a chance to register a listener for the versionchange event.

The firing of "success" or "error" events do not follow the normal steps to fire a success event or fire an error event as there is no active transaction at the time when they fire.

DOMString name

The name for the database

[EnforceRange] optional unsigned long long version

The version for the database

TypeError

The value of version is 0 (zero) or a negative number.

IDBOpenDBRequest deleteDatabase()

When invoked, this method MUST create a request and return it. The created request must implement the IDBOpenDBRequest interface and have its source set to null. The method then queues up an operation to run the steps for deleting a database. Let origin be the origin of the IDBEnvironment used to access this IDBFactory and name be the name parameter passed to this function.

If an error is returned from the steps above, the implementation MUST set the error attribute of the request to a DOMError whose name is the same as the error returned, and dispatch an event at the request. The event must use the Event interface and have its type set to "error". The event does bubble but is not cancelable. The propagation path of the event is just the request.

If the steps above are successful, the implementation MUST set the result of the request to undefined and fire a success event at the request. The event MUST implement the IDBVersionChangeEvent interface and have oldVersion set to database version and have the newVersion property set to null.

The firing of "success" or "error" events do not follow the normal steps to fire a success event or fire an error event as there is no active transaction at the time when they fire.

DOMString name

The name for the database

short cmp()

When invoked, this method MUST compare two keys. The method returns 1 if the first key is greater than the second, -1 if the first is less than the second, and 0 if the first is equal to the second.

any first

The first key to compare.

any second

The second key to compare.

DataError

One of the supplied keys was not a valid key.

Database

A database object can be used to manipulate the objects of that database. It is also the only way to obtain a transaction for that database.

readonly attribute DOMString name

On getting, this attribute MUST return the name of the connected database. The function MUST return this name even if the closePending flag is set on the connection. In other words, the return value from this function stays constant for the lifetime of the IDBDatabase instance.

readonly attribute unsigned long long version

On getting, this attribute MUST return the version of the database when this IDBDatabase instance was created. When a IDBDatabase instance is created, this is always the number passed as the version argument passed to the open call used to create the IDBDatabase instance. This value remains constant for the lifetime of the IDBDatabase object. If the connection is closed, this attribute represents a snapshot of the version that the database had when the connection was closed. Even if another connection is later used to modify the version, that attribute on closed instances are not changed.

readonly attribute DOMStringList objectStoreNames

On getting, this attribute MUST return a list of names of the object stores currently in the connected database. The list MUST be sorted in ascending order using the algorithm defined by step 4 of section 11.8.5, The Abstract Relational Comparison Algorithm of the ECMAScript Language Specification [[!ECMA-262]]. Once the closePending flag is set on the connection, this function MUST return a snapshot of the list of names of the object stores taken at the time when the close method was called. Even if other connections are later used to change the set of object stores that exist in the database. In other words, the return value from this function stays constant for the lifetime of the IDBDatabase instance, except during a "versionchange" transaction if createObjectStore or deleteObjectStore is called on this IDBDatabase instance itself.

IDBObjectStore createObjectStore()

This method creates and returns a new object store with the given name in the connected database. If this function is called from outside a "versionchange" transaction callback, or if this function is called on a IDBDatabase object other than that transaction's connection, the implementation MUST throw a DOMException of type InvalidStateError.

If an objectStore with the same name already exists, the implementation MUST throw a DOMException of type ConstraintError. Otherwise, the implementation MUST create a new object store and return an IDBObjectStore object representing it.

This method synchronously modifies the IDBDatabase.objectStoreNames property. However it only changes the IDBDatabase.objectStoreNames property on the IDBDatabase instance on which it was called.

If the optionalParameters argument is specified and has a keyPath property which is not undefined or null, then set keyPath to the value of this property. If keyPath is an Array, then each item in the array is converted to a string. If keyPath is not an Array, it is converted to a string.

If keyPath is not a valid key path then a DOMException of type SyntaxError MUST be thrown. Otherwise set the created object store's key path to the value of keyPath.

If the optionalParameters parameter is specified, and autoIncrement is set to true, and the keyPath parameter is specified to the empty string, or specified to an Array, this function MUST throw a InvalidAccessError exception.

In some implementations it's possible for the implementation to run into problems after queuing up an operation to create the object store after the createObjectStore function has returned. For example in implementations where metadata about the newly created objectStore is inserted into the database asynchronously, or where the implementation might need to ask the user for permission for quota reasons. Such implementations MUST still create and return an IDBObjectStore object. Instead, once the implementation realizes that creating the objectStore has failed, it MUST abort the transaction using the steps for aborting a transaction using the appropriate error as error parameter. For example if creating the object store failed due to quota reasons, QuotaError MUST be used as error.

DOMString name

The name of a new object store

optional IDBObjectStoreParameters optionalParameters

The options object whose attributes are optional parameters to this function. keyPath specifies the key path of the new object store. If the attribute is null, no key path is specified and thus keys are out-of-line. autoIncrement specifies whether the object store created should have a key generator.

InvalidStateError

This method was not called from a "versionchange" transaction callback. Also occurs if a request is made on a source object that has been deleted or removed.

ConstraintError

An object store with the same name, compared in a case-sensitive manner, already exists in the connected database.

InvalidAccessError

If autoIncrement is set to true, and keyPath either is the empty string, or an Array containing the empty string.

void deleteObjectStore()

This method destroys the object store with the given name in the connected database. If this function is called from outside a "versionchange" transaction callback, or if this function is called on a IDBDatabase object other than that transactions connection, the implementation MUST throw a DOMException of type InvalidStateError.

This method synchronously modifies the IDBDatabase.objectStoreNames property. However it only changes the IDBDatabase.objectStoreNames property on the IDBDatabase instance on which it was called.

DOMString name

The name of an existing object store

InvalidStateError

This method was not called from a "versionchange" transaction callback. Also occurs if a request is made on a source object that has been deleted or removed.

NotFoundError

There is no object store with the given name, compared in a case-sensitive manner, in the connected database.

IDBTransaction transaction()

This method, when called MUST execute the steps for creating a transaction in an asychronous fashion. The storeNames and mode arguments are forwarded to the algorithm as-is. The callback argument is set to null. The timeout argument is set to infinite. The connection argument is set to the IDBDatabase that the transaction() method was called on.

The method returns an IDBTransaction object representing the transaction returned by the steps above.

If this method is called on IDBDatabase object for which a "versionchange" transaction is still running, a InvalidStateError exception MUST be thrown. I.e. if a "versionchange" transaction is started when a database is opened and this method is called on the IDBDatabase instance for that transaction before the transaction is committed, a InvalidStateError exception MUST be thrown. Likewise, if this method is called on a IDBDatabase instance where the closePending flag is set, a InvalidStateError exception MUST be thrown.

any storeNames

The names of object stores and indexes in the scope of the new transaction

optional DOMString mode

The mode for isolating access to data inside the given object stores. If this parameter is not provided, the default access mode is "readonly".

InvalidStateError

The close() method has been called on this IDBDatabase instance.

NotFoundError

One of the names provided in the storeNames argument doesn't exist in this database.

TypeError

The value for the mode parameter is invalid.

InvalidAccessError

The function was called with an empty list of store names

void close()

This method returns immediately and performs the steps for closing a database connection.

[TreatNonCallableAsNull] attribute Function? onabort

The event handler for the abort event.

[TreatNonCallableAsNull] attribute Function? onerror

The event handler for the error event.

[TreatNonCallableAsNull] attribute Function? onversionchange

The event handler for the versionchange event.

Object Store

readonly attribute DOMString name

On getting, provide the name of this object store.

readonly attribute any keyPath

On getting, returns the key path of this object store. This will be either a DOMString, an Array of DOMStrings or null.

readonly attribute DOMStringList indexNames

On getting, provide a list of the names of indexes on objects in this object store. The list MUST be sorted in ascending order using the algorithm defined by step 4 of section 11.8.5, The Abstract Relational Comparison Algorithm of the ECMAScript Language Specification [[!ECMA-262]].

readonly attribute IDBTransaction transaction

On getting, returns the transaction this object store belongs to.

readonly attribute boolean autoIncrement;

On getting, provides the auto increment flag for this object store.

IDBRequest put()

This method throws a DOMException of type ReadOnlyError if the transaction which this IDBObjectStore belongs to is has its mode set to "readonly". If any of the following conditions are true, this method throws a DOMException of type DataError:

• The object store uses in-line keys and the key parameter was provided.
• The object store uses out-of-line keys and has no key generator and the key parameter was not provided.
• The object store uses in-line keys and the result of evaluating the object store's key path yields a value and that value is not a valid key.
• The object store uses in-line keys but no key generator and the result of evaluating the object store's key path does not yield a value.
• The key parameter was provided but does not contain a valid key.

Otherwise this method creates a structured clone of the value parameter. If the structured clone algorithm throws an exception, that exception is rethrown. Otherwise, run the steps for asynchronously executing a request and return the IDBRequest created by these steps. The steps are run with this IDBObjectStore as source and the steps for storing a record into an object store as operation, using this IDBObjectStore as store, the created clone as value, the key parameter as key, and with the no-overwrite flag flag set to false.

any value

The value to be stored in the record

optional any key

The key used to identify the record

TransactionInactiveError

The transaction this IDBObjectStore belongs to is not active.

ReadOnlyError

The mode of the associated transaction is "readonly".

DataError

The calculated key for the insertion was not a valid key.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

DataCloneError

The data being stored could not be cloned by the internal structured cloning algorithm.

IDBRequest add()

This method throws a DOMException of type ReadOnlyError if the transaction which this IDBObjectStore belongs to is has its mode set to "readonly". If any of the following conditions are true, this method throws a DOMException of type DataError:

• The object store uses in-line keys and the key parameter was provided.
• The object store uses out-of-line keys and has no key generator and the key parameter was not provided.
• The object store uses in-line keys and the result of evaluating the object store's key path yields a value and that value is not a valid key.
• The object store uses in-line keys but no key generator and the result of evaluating the object store's key path does not yield a value.
• The key parameter was provided but does not contain a valid key.

Otherwise this method creates a structured clone of the value parameter. If the structure clone algorithm throws an exception, that exception is rethrown. Otherwise, run the steps for asynchronously executing a request and return the IDBRequest created by these steps. The steps are run with this IDBObjectStore as source and the steps for storing a record into an object store as operation, using this IDBObjectStore as store, the created clone as value, the key parameter as key, and with the no-overwrite flag flag set to true.

To determine if a transaction has completed successfully, listen to the transaction’s complete event rather than the IDBObjectStore.add request’s success event, because the transaction may still fail after the success event fires.

any value

The value to be stored in the record

optional any key

The key used to identify the record

TransactionInactiveError

The transaction this IDBObjectStore belongs to is not active.

ReadOnlyError

The mode of the associated transaction is "readonly".

DataError

The calculated key for the insertion was not a valid key.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

DataCloneError

The data being stored could not be cloned by the internal structured cloning algorithm.

IDBRequest delete()

This method throws a ReadOnlyError if the transaction which this IDBObjectStore belongs to is has its mode set to "readonly". If the key parameter is not a valid key or a key range this method throws a DOMException of type DataError.

Otherwise this method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBObjectStore as source and the steps for deleting records from an object store as operation, using this IDBObjectStore as store and the key parameter as key.

Unlike other methods which take keys or key ranges, this method does not allow null to be passed as key. This is to reduce the risk that a small bug would clear a whole object store.

any key

Key identifying the record to be deleted

TransactionInactiveError

The transaction this IDBObjectStore belongs to is not active.

ReadOnlyError

The mode of the transaction this IDBObjectStore belongs to is "readonly".

IDBRequest get()

If the key parameter is not a valid key or a key range, this method throws a DOMException of type DataError. Otherwise, this method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBObjectStore as source and the steps for retrieving a value from an object store as operation, using this IDBObjectStore as store and the key parameter as key.

This function produces the same result if a record with the given key doesn't exist as when a record exists, but has undefined as value. If you need to tell the two situations apart, you can use openCursor with the same key. This will return a cursor with undefined as value if a record exists, or no cursor if no such record exists.

any key

Key identifying the record to be retrieved. This can also be an IDBKeyRange in which case the function retreives the first existing value in that range.

TransactionInactiveError

The transaction this IDBObjectStore belongs to is not active.

DataError

The key parameter was not passed a valid value.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

IDBRequest clear()

This method throws a DOMException of type ReadOnlyError if the transaction which this IDBObjectStore belongs to is has its mode set to "readonly".

Otherwise this method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBObjectStore as source and the steps for clearing an object store as operation, using this IDBObjectStore as store.

TransactionInactiveError

The transaction this IDBObjectStore belongs to is not active.

ReadOnlyError

The mode of the transaction this IDBObjectStore belongs to is "readonly".

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

IDBRequest openCursor()

If the range parameter is specified but is not a valid key or a key range, this method throws a DOMException of type DataError. Otherwise, this method creates a cursor. The cursor MUST implement the IDBCursorWithValue interface.

The newly created cursor MUST have an undefined position, a direction set to the value of the direction parameter, false as iterable flag value, and undefined key and value. The source of the cursor is the IDBObjectStore this function was called on.

If the range parameter is a key range then the cursor's range MUST be set to that range. Otherwise, if the range parameter is a valid key then the cursor's range is set to key range containing only that key value. If the range parameter is not specified, the cursor's key range is left as undefined.

This method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBObjectStore as source and the steps for iterating a cursor as operation, using the created cursor as cursor and with undefined as key.

optional any? range

The key range to use as the cursor's range

optional DOMString direction

The cursor's required direction

TransactionInactiveError

The transaction this IDBObjectStore belongs to is not active.

TypeError

The value for the direction parameter is invalid.

DataError

The range parameter was not passed key range or a valid key.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

IDBIndex createIndex()

This method creates and returns a new index with the given name and parameters in the connected database. If this function is called from outside a "versionchange" transaction callback, the implementation MUST throw an DOMException of type InvalidStateError exception. If an index with the same name already exists, the implementation MUST throw a DOMException of type ConstraintError. Otherwise, the implementation MUST create a new index and return an IDBIndex object representing it. The created index has its unique and multiEntry flags are set to the values of the unique and multiEntry properties in the optionalParameters argument.

If the keyPath argument is an Array, then each item in the array is converted to a DOMString. If keyPath is not an Array, it is converted to a DOMString.

If keyPath is not a valid key path then a DOMException of type SyntaxError MUST be thrown. Otherwise set the created object store's key path to the value of keyPath. If keyPath is an Array and the multiEntry property in the optionalParameters is true, then a DOMException of type InvalidAccessError MUST be thrown. Otherwise set the created index's key path to the value of keyPath.

The index that is requested to be created can contain constraints on the data allowed in the index's referenced object store, such as requiring uniqueness of the values referenced by the index's keyPath. If the referenced object store already contains data which violates these constraints, this MUST NOT cause the implementation of createIndex to throw an exception or affect what it returns. The implementation MUST still create and return an IDBIndex object. Instead the implementation must queue up an operation to abort the "versionchange" transaction which was used for the createIndex call.

This method will synchronously modify the IDBObjectStore.indexNames property.

In some implementations it's possible for the implementation to asynchronously run into problems creating the index after the createIndex function has returned. For example in implementations where metadata about the newly created index is queued up to be inserted into the database asynchronously, or where the implementation might need to ask the user for permission for quota reasons. Such implementations MUST still create and return an IDBIndex object. Instead, once the implementation realizes that creating the index has failed, it MUST abort the transaction using the steps for aborting a transaction using the appropriate error as error parameter. For example if creating the index failed due to quota reasons, QuotaError MUST be used as error and if the index can't be created due to unique constraints, ConstraintError MUST be used as error.

DOMString name

The name of a new index

any keyPath

The key path used by the new index.

optional IDBIndexParameters optionalParameters

The options object whose attributes are optional parameters to this function. unique specifies whether the index's unique flag is set. multiEntry specifies whether the index's multiEntry flag is set.

InvalidStateError

This method was not called from a "versionchange" transaction callback. Also occurs if a request is made on a source object that has been deleted or removed.

ConstraintError

An index with the same name, compared in a case-sensitive manner, already exists in the connected database.

IDBIndex index()

Returns an IDBIndex representing an index that is part of the object store. Every call to this function on the same IDBObjectStore instance and with the same name returns the same IDBIndex instance. However the retured IDBIndex instance is specific to this IDBObjectStore instance. If this function is called on a different IDBObjectStore instance, a different IDBIndex instance is returned. A result of this is that different IDBTransactions use different IDBIndex instances to represent the same index.

DOMString name

The name of an existing index

NotFoundError

There is no index with the given name, compared in a case-sensitive manner, in the connected database.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed, or if the transaction the object store belongs to has finished.

void deleteIndex()

This method destroys the index with the given name in the connected database. Note that this method must only be called from a "versionchange" transaction callback.

This method will synchronously modify the IDBObjectStore.indexNames property.

DOMString indexName

The name of an existing index

InvalidStateError

This method was not called from a "versionchange" transaction callback.

NotFoundError

There is no index with the given name, compared in a case-sensitive manner, in the connected database.

IDBRequest count()

If the optional key parameter is not a valid key or a key range, this method throws a DOMException of type DataError. This method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBObjectStore as source and the steps for iterating a cursor as operation, using the created cursor as cursor. If provided, use the key parameter as key, otherwise, use undefined as key. If the result of the algorithm is null return 0 (zero) as the result for the request. Otherwise, use the return cursor to determine the total number of objects that share the key or key range and return that value as the result for the request.

optional any key

Key identifying the record to be retrieved. This can also be an IDBKeyRange.

TransactionInactiveError

The transaction this IDBObjectStore belongs to is not active.

DataError

The key parameter is not a valid key or a key range.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

Index

Index objects implement the following interface:

readonly attribute DOMString name

On getting, provide the name of this index.

readonly attribute IDBObjectStore objectStore

On getting, returns a reference to the IDBObjectStore instance for the referenced object store in this IDBIndex's transaction. This MUST return the same IDBObjectStore instance as was used to get a reference to this IDBIndex.

readonly attribute any keyPath

On getting, returns the key path of this index. This will be either a DOMString or an Array of DOMStrings.

readonly attribute boolean multiEntry

On getting, provide the multiEntry flag of this index.

readonly attribute boolean unique

On getting, provide the unique flag of this index.

IDBRequest openCursor()

If the range parameter is specified but is not a valid key or a key range, this method throws a DOMException of type DataError. Otherwise, this method creates a cursor. The cursor MUST implement the IDBCursorWithValue interface.

The newly created cursor MUST have an undefined position, a direction set to the value of the direction parameter, false as iterable flag value, and undefined key and value. The source of the cursor is the IDBIndex this function was called on.

If the range parameter is a key range then the cursor's range is set to that range. Otherwise, if the range parameter is a valid key then the cursor's range is set to key range containing only that key value. If the range parameter is not specified, the cursor's key range is left as undefined.

This method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBIndex as source and the steps for iterating a cursor as operation, using the created cursor as cursor and with undefined as key

optional any? range

The key range to use as the cursor's range

optional DOMString direction

The cursor's required direction

TransactionInactiveError

The transaction this IDBIndex belongs to is not active.

TypeError

The value for the direction parameter is invalid.

DataError

The range parameter was not passed key range or a valid key.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

IDBRequest openKeyCursor()

If the range parameter is specified but is not a valid key or a key range, this method throws a DOMException of type DataError. Otherwise, this method creates a cursor. The cursor MUST implement the IDBCursor interface, but MUST NOT implement the IDBCursorWithValue interface.

The newly created cursor MUST have an undefined position, a direction set to the value of the direction parameter, false as iterable flag value, and undefined key and value. The source of the cursor is the IDBIndex this function was called on.

If the range parameter is a key range then the cursor's range is set to that range. Otherwise, if the range parameter is a valid key then the cursor's range is set to key range containing only that key value. If the range parameter is not specified, the cursor's key range is left as undefined.

This method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBObjectStore as source and the steps for iterating a cursor as operation, using the created cursor as cursor and with undefined as key

optional any? range

The key range to use as the cursor's range

optional DOMString direction

The cursor's required direction

TransactionInactiveError

The transaction this IDBIndex belongs to is not active.

TypeError

The value for the direction parameter is invalid.

DataError

The range parameter was not passed key range or a valid key.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

IDBRequest get()

If the key parameter is not a valid key or a key range, this method throws a DOMException of type DataError. This method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBObjectStore as source and the steps for retrieving a referenced value from an index as operation, using this IDBIndex as index and the key parameter as key.

This function produces the same result if a record with the given key doesn't exist as when a record exists, but has undefined as value. If you need to tell the two situations apart, you can use openCursor with the same key. This will return a cursor with undefined as value if a record exists, or no cursor if no such record exists.

any key

Key identifying the record to be retrieved. This can also be an IDBKeyRange in which case the function retreives the first existing value in that range.

TransactionInactiveError

The transaction this IDBIndex belongs to is not active.

DataError

The key parameter was not passed a valid value.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

IDBRequest getKey()

Gets the primary key of the record from the referenced object store entry.

If the key parameter is not a valid key or a key range, this method throws a DOMException of type DataError. This method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBObjectStore as source and the steps for retrieving a value from an index as operation, using this IDBIndex as index and the key parameter as key.

any key

Key identifying the record to be retrieved. This can also be an IDBKeyRange in which case the function retreives the first existing value in that range.

TransactionInactiveError

The transaction this IDBIndex belongs to is not active.

DataError

The key parameter was not passed a valid value.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

IDBRequest count()

If the optional key parameter is not a valid key or a key range, this method throws a DOMException of type DataError. This method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBIndex as source and the steps for iterating a cursor as operation, using the created cursor as cursor. If provided, use the key parameter as key, otherwise, use undefined as key. If the result of the algorithm is null return 0 (zero) as the result for the request. Otherwise, use the return cursor to determine the total number of objects that share the key or key range and return that value as the result for the request.

optional any key

Key identifying the record to be retrieved. This can also be an IDBKeyRange.

TransactionInactiveError

The transaction this IDBIndex belongs to is not active.

DataError

The key parameter is not a valid key or a key range.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

Cursor

Cursor objects implement the following interface:

readonly attribute object source

On getting, returns the IDBObjectStore or IDBIndex which this cursor is iterating. This function never returns null or throws an exception, even if the cursor is currently being iterated, has iterated past its end, or its transaction is not active.

readonly attribute DOMString direction

On getting, provide the traversal direction of the cursor.

readonly attribute any key

Returns the cursor's current key. Note that if this property returns an object (specifically an Array), it returns the same object instance every time it is inspected, until the cursor's key is changed. This means that if the object is modified, those modifications will be seen by anyone inspecting the value of the cursor. However modifying such an object does not modify the contents of the database.

readonly attribute any primaryKey

Returns the cursor's current effective key. Note that if this property returns an object (specifically an Array), it returns the same object instance every time it is inspected, until the cursor's effective key is changed. This means that if the object is modified, those modifications will be seen by anyone inspecting the value of the cursor. However modifying such an object does not modify the contents of the database.

IDBRequest update()

This method throws a DOMException of type ReadOnlyError if the transaction which this IDBCursor belongs to has its mode set to "readonly". If this cursor's got value flag is false or if this cursor was created using openKeyCursor. This method throws a DOMException of type InvalidStateError. If the effective object store of this cursor uses in-line keys and evaluating the key path of the value parameter results in a different value than the cursor's effective key, this method throws a DOMException of type DataError.

Otherwise this method creates a structured clone of the value parameter. If the structured clone algorithm throws an exception, that exception is rethrown. Otherwise, run the steps for asynchronously executing a request and return the IDBRequest created by these steps. The steps are run with this IDBCursor as source and the steps for storing a record into an object store as operation, using this cursor's effective object store as store, the created clone as value, this cursor's effective key as key, and with the no-overwrite flag flag set to false.

A result of running the steps for storing a record into an object store is that if the record has been deleted since the cursor moved to it, a new record will be created.

any value

The new value to store at the current position.

TransactionInactiveError

The transaction this IDBCursor belongs to is not active.

ReadOnlyError

The mode of the transaction this IDBCursor belongs to is "readonly"

InvalidStateError

Thrown if cursor was created using openKeyCursor or if the cursor is currently being iterated or has iterated past the end.

DataError

The underlying object store uses in-line keys and the property in value at the object store's key path does not match the key in this cursor's position.

DataCloneError

The data being stored could not be cloned by the internal structured cloning algorithm.

void advance()

This method runs the steps for asynchronously executing a request. However, the steps are slightly modified such that instead of creating a new IDBRequest, it reuses the request originally created when this cursor was created. The done flag on the request is set to false before the request is returned. The steps are run with the cursor's source as source. The operation runs the steps for iterating a cursor count number of times with null as key and this cursor as cursor.

Before this method returns, unless an exception was thrown, it sets the got value flag on the cursor to false.

Calling this method more than once before new cursor data has been loaded is not allowed and results in a DOMException of type InvalidStateError being thrown. For example, calling advance() twice from the same onsuccess handler results in a DOMException of type InvalidStateError being thrown on the second call.

If the value for count is 0 (zero) or a negative number, this method MUST throw a JavaScript TypeError exception.

[EnforceRange] unsigned long count

The number of advances forward the cursor should make.

TypeError

The value passed into the count parameter was zero or a negative number.

TransactionInactiveError

The transaction this IDBCursor belongs to is not active.

InvalidStateError

The cursor is currently being iterated, or has iterated past its end.

void continue()

If this cursor's got value flag is false, this method throws a DOMException of type InvalidStateError. If the key parameter is specified and fulfills any of these conditions this method MUST throw a DOMException of type DataError:

• The parameter is not a valid key.
• The parameter is less than or equal to this cursor's position and this cursor's direction is "next" or "nextunique".
• The parameter is greater than or equal to this cursor's position and this cursor's direction is "prev" or "prevunique".

Otherwise this method runs the steps for asynchronously executing a request. However, the steps are slightly modified such that instead of creating a new IDBRequest, it reuses the request originally created when this cursor was created. The done flag on the request is set to false before the request is returned. The steps are run with the cursor's source as source and the steps for iterating a cursor as operation, using this cursor as cursor and the key parameter as key.

Before this method returns, unless an exception was thrown, it sets the got value flag on the cursor to false.

Calling this method more than once before new cursor data has been loaded is not allowed and results in a DOMException of type InvalidStateError being thrown. For example, calling continue() twice from the same onsuccess handler results in a DOMException of type InvalidStateError being thrown on the second call.

optional any key

The next key to position this cursor at

TransactionInactiveError

The transaction this IDBCursor belongs to is not active.

InvalidStateError

The cursor is currently being iterated, or has iterated past its end.

DataError

The key parameter was specified but did not contain a valid key.

IDBRequest delete()

This method throws a DOMException of type ReadOnlyError if the transaction which this IDBCursor belongs to has its mode set to "readonly". If this cursor's got value flag is false, or if this cursor was created using openKeyCursor a DOMException of type InvalidStateError is thrown.

Otherwise this method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBCursor as source and the steps for deleting records from an object store as operation, using this cursor's effective object store and effective key as store and key respectively.

TransactionInactiveError

The transaction this IDBCursor belongs to is not active.

ReadOnlyError

The mode of the transaction this IDBCursor belongs to is "readonly".

InvalidStateError

The cursor was created using openKeyCursor or the cursor is currently being iterated or has iterated past the end.

readonly attribute any value

Returns the cursor's current value. Note that if this property returns an object, it returns the same object instance every time it is inspected, until the cursor's value is changed. This means that if the object is modified, those modifications will be seen by anyone inspecting the value of the cursor. However modifying such an object does not modify the contents of the database.

Transaction

Transaction objects implement the following interface:

readonly attribute enum mode

On getting, provide the mode for isolating access to data inside the object stores that are in the scope of the transaction.

readonly attribute IDBDatabase db

The database connection of which this transaction is a part

readonly attribute DOMError error

If this transaction is not finished, is finished but was successfully committed, or was aborted due to a call to the abort function, this property returns null. If this transaction was aborted due to a failed request, this property returns the same DOMError as the request which caused this transaction to be aborted. If this transaction was aborted due to an error when committing the transaction, and not due to a failed request, this property returns a DOMError which contains the reason for the transaction failure (e.g. QuotaExceededError or UnknownError).

IDBObjectStore objectStore()

Returns an IDBObjectStore representing an object store that is part of the scope of this transaction. Every call to this function on the same IDBTransaction instance and with the same name returns the same IDBObjectStore instance. However the returned IDBObjectStore instance is specific to this IDBTransaction. If this function is called on a different IDBTransaction, a different IDBObjectStore instance is returned.

DOMString name

The requested object store

NotFoundError

If the requested object store is not in this transaction's scope.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed, or if the transaction has finished.

void abort()

If this transaction is finished, throw a DOMException of type InvalidStateError. Otherwise this method sets the transaction's active flag to false and aborts the transaction by running the steps for aborting a transaction with the error parameter set to null.

InvalidStateError

If this transaction has already been committed or aborted.

[TreatNonCallableAsNull] attribute Function? onabort

The event handler for the abort event.

[TreatNonCallableAsNull] attribute Function? oncomplete

The event handler for the complete event.

To determine if a transaction has completed successfully, listen to the transaction’s complete event rather than the IDBObjectStore.add request’s success event, because the transaction may still fail after the success event fires.

[TreatNonCallableAsNull] attribute Function? onerror

The event handler for the error event.

Opening a database

WorkerUtils objects MUST implement the IDBEnvironmentSync interface.

readonly attribute IDBFactorySync indexedDBSync

This attribute provides applications a mechanism for accessing capabilities of indexed databases.

IDBDatabaseSync open()

When invoked, this method MUST throw a DOMException of type InvalidStateError when it is called within the IDBTransactionCallback of a transaction method or the IDBVersionChangeCallback of a open method. Otherwise this method synchronously runs the steps for opening a database. Let origin be the origin of the IDBEnvironmentSync used to access this IDBFactorySync, name, version and upgrade callback be the name, version and upgradeCallback arguments passed to this function.

If no version is specified and a database exists, use the current database version and follow the steps for opening a database. If no version is specified and no database exists, set database version to 1, follow the steps for opening a database, and return a database without object stores.

If a timeout parameter was supplied, then this limits the total waiting time allowed in step 3 of steps for opening a database and step 4 of the steps for running a "versionchange" transaction. If more waiting time would be needed in order to progress, then abort those algorithms and throw a DOMException of type TimeoutError.

The timeout parameter does not affect how long the upgradeCallback can run.

If an error is returned from the steps above, then the implementation MUST throw a DOMException with its name and message set to appropriate values for the error.

If the steps above are successful, the implementation MUST create an IDBDatabaseSync object representing the created connection and return it.

Processing a open call may take a long time as it could require running a "versionchange" transaction which requires all other connections to the database to be closed, which in turn may depend on user input or other long-running tasks. If blocking for a long period of time is not acceptable for a given scenario then the asynchronous API should be used for version changes.

If the value for version is 0 (zero) or a negative number, this method MUST throw a JavaScript TypeError exception.

DOMString name

The name for the database

[EnforceRange] optional unsigned long long version

The version for the database

IDBVersionChangeCallback upgradeCallback

Callback used if the database version needs to be upgraded before the database can be opened.

optional unsigned long timeout

Defines a transaction timeout value in milliseconds that will limit the how long waiting for the "versionchange" transaction. If the parameter is not provided, the value of timeout is infinite.

InvalidStateError

The open method was called within the IDBTransactionCallback of a transaction method or IDBVersionChangeCallback of a open method.

TimeoutError

Was unable to open the database with the requested version within the given timeout period.

TypeError

The value of version is 0 (zero) or a negative number.

void deleteDatabase()

When invoked, this method synchronously runs the steps for deleting a database. Let origin be the origin of the IDBEnvironmentSync used to access this IDBFactorySync and name be the name argument passed to this function.

If an error is returned from the steps above, then the implementation MUST throw a DOMException with its name and message set to appropriate values for the error.

DOMString name

The name of the database to be deleted.

short cmp()

When invoked, this method MUST compare two keys. The method returns 1 if the first key is greater than the second, -1 if the first is less than the second, and 0 if the first is equal to the second.

any first

The first key to compare.

any second

The second key to compare.

DataError

One of the supplied keys was not a valid key.

Database

A database object provides access to the schema and data of a particular database.

readonly attribute DOMString name

On getting, this attribute MUST return the name of the connected database. The function MUST return this name even if the closePending flag is set on the connection. In other words, the return value from this function stays constant for the lifetime of the IDBDatabaseSync instance.

readonly attribute unsigned long long version

On getting, this attribute MUST return the version of the database when this IDBDatabaseSync instance was created. When a IDBDatabaseSync instance is created, this is always the number passed as the version argument passed to the open call used to create the IDBDatabaseSync instance. This value remains constant for the lifetime of the IDBDatabaseSync object. If the connection is closed, this attribute represents a snapshot of the version that the database had when the connection was closed. Even if another connection is later used to modify the version, that attribute on closed instances are not changed.

readonly attribute DOMStringList objectStoreNames

On getting, this attribute MUST return a list of names of the object stores currently in the connected database. The list MUST be sorted in ascending order using the algorithm defined by step 4 of section 11.8.5, The Abstract Relational Comparison Algorithm of the ECMAScript Language Specification [[!ECMA-262]]. Once the closePending flag is set on the connection, this function MUST return a snapshot of the list of names of the object stores taken at the time when the close method was called. Even if other connections are later used to change the set of object stores that exist in the database. In other words, the return value from this function stays constant for the lifetime of the IDBDatabaseSync instance except during a "versionchange" transaction if createObjectStore or deleteObjectStore is called on this IDBDatabaseSync instance itself.

IDBObjectStoreSync createObjectStore()

This method creates and returns a new object store with the given name in the connected database. This method should only be called from inside a "versionchange" transaction.

This method synchronously modifies the IDBDatabaseSync.objectStoreNames property. However it only modifies the IDBDatabaseSync.objectStoreNames property on the IDBDatabaseSync instance on which it was called.

If the optionalParameters argument is specified and has a keyPath property which is not null, then set keyPath to the value of this property. If keyPath is an Array, then each item in the array is converted to a string. If keyPath is not an Array, it is converted to a string.

If keyPath is not a valid key path then a DOMException of type SyntaxError MUST be thrown. Otherwise set the created object store's key path to the value of keyPath.

If the optionalParameters parameter is specified, and autoIncrement is set to true, and the keyPath parameter is specified to the empty string, or specified to an Array, this function MUST throw a InvalidAccessError exception.

DOMString name

The name of a new object store

optional IDBObjectStoreParameters optionalParameters

The options object whose attributes are optional parameters to this function. keyPath specifies the key path of the new object store. If the attribute is null no key path is specified and thus keys are out-of-line. autoIncrement specifies whether the object store created should have a key generator.

InvalidStateError

This method was not called from a "versionchange" transaction. Also occurs if a request is made on a source object that has been deleted or removed.

ConstraintError

If an object store with the same name, compared in a case-sensitive manner, already exists in the connected database.

InvalidAccessError

If autoIncrement is set to true, and keyPath either is the empty string, or an Array containing the empty string.

void deleteObjectStore()

This method destroys an object store with the given name as well as all indexes that are referencing that object store. This method should only be called from inside a "versionchange" transaction.

This method synchronously modifies the IDBDatabaseSync.objectStoreNames property. However it only modifies the IDBDatabaseSync.objectStoreNames property on the IDBDatabaseSync instance on which it was called.

DOMString name

The name of an existing object store

InvalidStateError

This method was not called from a "versionchange" transaction callback. Also occurs if a request is made on a source object that has been deleted or removed.

NotFoundError

If the object store with the given name, compared in a case-sensitive manner, does not already exist in the connected database.

void transaction()

This method, when called MUST execute the steps for creating a transaction in a sychronous fashion. The storeNames, callback, mode, and timeout arguments are forwarded to the algorithm as-is. The connection argument is set to the IDBDatabaseSync that the transaction() method was called on.

The method returns an IDBTransactionSync object representing the transaction returned by the steps above.

This method MUST throw an DOMException of type InvalidStateError when it is called within the IDBTransactionCallback of a transaction method or the IDBVersionChangeCallback of a open method.

any storeNames

The names of object stores and indexes in the scope of the new transaction

IDBTransactionCallback callback

A callback which will be called with the newly created transaction. When the callback returns, the transaction is committed.

optional DOMString mode

The mode for isolating access to data inside the given object stores. If this parameter is not provided, the default access mode is "readonly".

optional unsigned long timeout

The interval in milliseconds which this operation is allowed to take to reserve all the database objects identified in the new transaction's scope. The default is user agent specific

TimeoutError

If starting the transaction takes longer than the specified timeout.

InvalidStateError

The close() method has been called on this IDBDatabase instance. Also thrown when The transaction() method was called within the IDBTransactionCallback of a transaction method or the IDBVersionChangeCallback of a open method.

NotFoundError

One of the names provided in the storeNames argument doesn't exist in this database.

TypeError

The value for the mode parameter is invalid.

InvalidAccessError

The function was called with an empty list of store names

void close()

This method synchronously performs the steps for closing a database connection and returns once the database has been closed.

void transactionStarted()

Called once the transaction is allowed to run. The actions taken in this function make up the body of the transaction.

IDBTransactionSync transaction

The newly started transaction

void transactionStarted()

Called if a database upgrade is needed once the transaction used to upgrade the database is allowed to run. The actions taken in this function make up the body of the transaction.

IDBTransactionSync transaction

The newly started transaction

unsigned long long oldVersion

The version that the database had before the upgrade was needed. 0 if the database was newly created.

Object Store

readonly attribute DOMString name

On getting, provide the name of this object store.

readonly attribute any keyPath

On getting, provide the key path of this object store. This will be either a DOMString, an Array of DOMStrings or null.

readonly attribute DOMStringList indexNames

On getting, provide a list of the names of indexes on objects in this object store. The list MUST be sorted in ascending order using the algorithm defined by step 4 of section 11.8.5, The Abstract Relational Comparison Algorithm of the ECMAScript Language Specification [[!ECMA-262]].

readonly attribute IDBTransactionSync transaction

On getting, returns the transaction this object store belongs to.

readonly attribute boolean autoIncremenent;

On getting, provides the auto increment flag for this object store.

any put()

This method throws a DOMException of type ReadOnlyError if the transaction which this IDBObjectStoreSync belongs to has its mode set to "readonly". If any of the following conditions are true, this method throws a DOMException of type DataError:

• The object store uses in-line keys and the key parameter was provided.
• The object store uses out-of-line keys and has no key generator and the key parameter was not provided.
• The object store uses in-line keys and the result of evaluating the object store's key path yields a value and that value is not a valid key.
• The object store uses in-line keys but no key generator and the result of evaluating the object store's key path does not yield a value.
• The key parameter was provided but does not contain a valid key.

Otherwise this method creates a structured clone of the value parameter. If the structured clone algorithm throws an exception, that exception is rethrown. Otherwise, run the steps for synchronously executing a request and return the result, in this case the key of the stored object. The steps are run with this IDBObjectStoreSync as source and the steps for storing a record into an object store as operation, using this IDBObjectStoreSync as store, the created clone as value, the key parameter as key, and with the no-overwrite flag flag set to false.

any value

The value to be stored in the record

optional any key

The key used to identify the record

TransactionInactiveError

The transaction this IDBObjectStoreSync belongs to is not active.

ReadOnlyError

The mode of the associated transaction is "readonly".

DataError

The calculated key for the insertion was not a valid key.

ConstraintError

Another record in this object store has the same value for the keyPath of a unique index.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

DataCloneError

The data being stored could not be cloned by the internal structured cloning algorithm.

any add()

This method throws a DOMException of type ReadOnlyError if the transaction which this IDBObjectStoreSync belongs to is has its mode set to "readonly". If any of the following conditions are true, this method throws a DOMException of type DataError:

• The object store uses in-line keys and the key parameter was provided.
• The object store uses out-of-line keys and has no key generator and the key parameter was not provided.
• The object store uses in-line keys and the result of evaluating the object store's key path yields a value and that value is not a valid key.
• The object store uses in-line keys but no key generator and the result of evaluating the object store's key path does not yield a value.
• The key parameter was provided but does not contain a valid key.

Otherwise this method creates a structured clone of the value parameter. If the structured clone algorithm throws an exception, that exception is rethrown. Otherwise, run the steps for synchronously executing a request and return the key of the stored object. The steps are run with this IDBObjectStoreSync as source and the steps for storing a record into an object store as operation, using this IDBObjectStoreSync as store, the created clone as value, the key parameter as key, and with the no-overwrite flag flag set to true.

any value

The value to be stored in the record

optional any key

The key used to identify the record

TransactionInactiveError

The transaction this IDBObjectStoreSync belongs to is not active.

ReadOnlyError

The mode of the associated transaction is "readonly".

DataError

The calculated key for the insertion was not a valid key.

ConstraintError

A record exists in this object store for the key key parameter, or another record in this object store has the same value for the keyPath of a unique index.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

DataCloneError

The data being stored could not be cloned by the internal structured cloning algorithm.

boolean delete()

This method throws a DOMException of type ReadOnlyError if the transaction which this IDBObjectStoreSync belongs to is has its mode set to "readonly". If the key parameter is not a valid key or a key range this method throws a DOMException of type DataError.

Otherwise this method runs the steps for synchronously executing a request. The steps are run with this IDBObjectStoreSync as source and the steps for deleting records from an object store as operation, using this IDBObjectStoreSync as store and the key parameter as key. The function returns the result of running these steps.

Unlike other methods which take keys or key ranges, this method does not allow null to be passed as key. This is to reduce the risk that a small bug would clear a whole object store.

any key

Key identifying the record to be deleted

TransactionInactiveError

The transaction this IDBObjectStoreSync belongs to is not active.

ReadOnlyError

The mode of the transaction this IDBObjectStoreSync belongs to is "readonly".

NotFoundError

A record did not exist in this object store for the key key parameter.

any get()

If the key parameter is not a valid key or a key range, this method throws a DOMException of type DataError. Otherwise, this method runs the steps for synchronously executing a request and returns the result of the operation. The steps are run with this IDBObjectStoreSync as source and the steps for retrieving a value from an object store as operation, using this IDBObjectStoreSync as store and the key parameter as key.

This function produces the same result if a record with the given key doesn't exist as when a record exists, but has undefined as value. If you need to tell the two situations apart, you can use openCursor with the same key. This will return a cursor with undefined as value if a record exists, or no cursor if no such record exists.

any key

Key identifying the record to be retrieved. This can also be an IDBKeyRange in which case the function retrieves the first existing value in that range.

TransactionInactiveError

The transaction this IDBObjectStoreSync belongs to is not active.

DataError

The key parameter was not passed a valid value.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

void clear()

This method throws a DOMException of type ReadOnlyError if the transaction which this IDBObjectStoreSync belongs to is has its mode set to "readonly".

Otherwise this method runs the steps for synchronously executing a request. The steps are run with this IDBObjectStoreSync as source and the steps for clearing an object store as operation, using this IDBObjectStoreSync as store.

TransactionInactiveError

The transaction this IDBObjectStoreSync belongs to is not active.

ReadOnlyError

The mode of the transaction this IDBObjectStoreSync belongs to is "readonly".

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

IDBIndexSync createIndex()

This creates and returns a new index with the given name and parameters in the connected database. Note that this method must only be called from a "versionchange" transaction. The created index has its unique and multiEntry flags are set to the values of the unique and multiEntry properties in the optionalParameters argument.

If the keyPath argument is an Array, then each item in the array is converted to a DOMString. If keyPath is not an Array, it is converted to a DOMString.

If keyPath is not a valid key path then a DOMException of type SyntaxError MUST be thrown. Otherwise set the created object store's key path to the value of keyPath. If keyPath is an Array and the multiEntry property in the optionalParameters is true, then a DOMException of type InvalidAccessError MUST be thrown. Otherwise set the created index's key path to the value of keyPath.

DOMString name

The name of a new index

any keyPath

The key path used by the new index

optional IDBIndexParameters optionalParameters

The options object whose attributes are optional parameters to this function. unique specifies whether the index's unique flag is set. multiEntry specifies whether the index's multiEntry flag is set.

InvalidStateError

This method was not called from a "versionchange" transaction. Also occurs if a request is made on a source object that has been deleted or removed.

ConstraintError

An index with the same name, compared in a case-sensitive manner, already exists in the connected database. Also thrown when creating a unique index on top of an object store that already contains records that violate the unique constraint.

IDBIndexSync index()

Returns an IDBIndexSync representing an index that is part of the object store. Every call to this function on the same IDBObjectStoreSync instance and with the same name returns the same IDBIndexSync instance. However the retured IDBIndexSync instance is specific to this IDBObjectStoreSync instance. If this function is called on a different IDBObjectStoreSync instance, a different IDBIndexSync instance is returned. A result of this is that different IDBTransactionSyncs use different IDBIndexSync instances to represent the same index.

DOMString name

The name of an existing index

NotFoundError

If the index with the given name does not exist in the connected database.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed, or if the transaction the object store belongs to has finished.

void deleteIndex()

This method destroys the index with the given name in the connected database. Note that this method must only be called from a "versionchange" transaction.

DOMString indexName

The name of an existing index

NotFoundError

If the index with the given name does not exist in the connected database.

InvalidStateError

This method was not called from a "versionchange" transaction.

IDBCursorWithValueSync openCursor()

If the range parameter is specified but is not a valid key or a key range, this method throws a DOMException of type DataError. Otherwise, this method creates a cursor. The cursor MUST implement the IDBCursorWithValueSync interface.

The newly created cursor MUST have an undefined position, a direction set to the value of the direction parameter, false as iterable flag value, and undefined key and value. The source of the cursor is the IDBObjectStoreSync this function was called on.

If the range parameter is a key range then the cursor's range is set to that range. Otherwise, if the range parameter is a valid key then the cursor's range is set to key range containing only that key value. If the range parameter is not specified, the cursor's key range is left as undefined.

This method runs the steps for synchronously executing a request and returns the result of the operation, in this case an IDBCursorSync object. The steps are run with this IDBObjectStoreSync as source and the steps for iterating a cursor as operation, using the created cursor as cursor and with undefined as key.

optional any? range

The key range to use as the cursor's range

optional DOMString direction

The cursor's required direction

TransactionInactiveError

The transaction this IDBObjectStoreSync belongs to is not active.

TypeError

The value for the direction parameter is invalid.

DataError

The range parameter was not passed key range or a valid key.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

unsigned long count()

If the optional key parameter is not a valid key or a key range, this method throws a DOMException of type DataError. This method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBObjectStore as source and the steps for iterating a cursor as operation, using the created cursor as cursor. If provided, use the key parameter as key, otherwise, use undefined as key. If the result of the algorithm is null return 0 (zero) as the result for the request. Otherwise, use the return cursor to determine the total number of objects that share the key or key range and return that value as the result for the request.

optional any key

Key identifying the record to be retrieved. This can also be an IDBKeyRange.

TransactionInactiveError

The transaction this IDBObjectStoreSync belongs to is not active.

DataError

The key parameter is not a valid key or a key range.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

Index

readonly attribute DOMString name

On getting, provide the name of this index.

readonly attribute IDBObjectStoreSync objectStore

On getting, returns a reference to the IDBObjectStoreSync instance for the referenced object store in this IDBIndexSync's transaction. This MUST return the same IDBObjectStoreSync instance as was used to get a reference to this IDBIndexSync.

readonly attribute any keyPath

On getting, returns the key path of this index. This will be either a DOMString or an Array of DOMStrings.

readonly attribute boolean multiEntry

On getting, provide the multiEntry flag of this index.

readonly attribute boolean unique

On getting, provide the unique flag of this index.

IDBCursorWithValueSync openCursor()

If the range parameter is specified but is not a valid key or a key range, this method throws a DOMException of type DataError. Otherwise, this method creates a cursor. The cursor MUST implement the IDBCursorWithValueSync interface.

The newly created cursor MUST have an undefined position, a direction set to the value of the direction parameter, false as iterable flag value, and undefined key and value. The source of the cursor is the IDBIndexSync this function was called on.

If the range parameter is a key range then the cursor's range is set to that range. Otherwise, if the range parameter is a valid key then the cursor's range is set to key range containing only that key value. If the range parameter is not specified, the cursor's key range is left as undefined.

This method runs the steps for synchronously executing a request and returns the result, in this case a cursor object. The steps are run with this IDBIndexSync as source and the steps for iterating a cursor as operation, using the created cursor as cursor and with undefined as key

optional any? range

The key range to use as the cursor's range

optional DOMString direction

The cursor's required direction

TransactionInactiveError

The transaction this IDBIndexSync belongs to is not active.

TypeError

The value for the direction parameter is invalid.

DataError

The range parameter was not passed a valid value.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

IDBCursorSync openKeyCursor()

If the range parameter is specified but is not a valid key or a key range, this method throws a DOMException of type DataError. Otherwise, this method creates a cursor. The cursor MUST implement the IDBCursorSync interface and MUST NOT implement the IDBCursorWithValueSync interface.

The newly created cursor MUST have an undefined position, a direction set to the value of the direction parameter, false as iterable flag value, and undefined key and value. The source of the cursor is the IDBIndexSync this function was called on.

If the range parameter is a key range then the cursor's range is set to that range. Otherwise, if the range parameter is a valid key then the cursor's range is set to key range containing only that key value. If the range parameter is not specified, the cursor's key range is left as undefined.

This method runs the steps for synchronously executing a request and returns the result, in this case a cursor object. The steps are run with this IDBIndexSync as source and the steps for iterating a cursor as operation, using the created cursor as cursor and with undefined as key

optional any? range

The key range to use as the cursor's range

optional DOMString direction

The cursor's required direction

TransactionInactiveError

The transaction this IDBIndexSync belongs to is not active.

TypeError

The value for the direction parameter is invalid.

DataError

The range parameter was not passed key range or a valid key.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

any get()

If the key parameter is not a valid key or a key range, this method throws a DOMException of type DataError. This method runs the steps for synchronously executing a request and returns the result from that, in this case an object from the underlying store. The steps are run with this IDBIndexSync as source and the steps for retrieving a referenced value from an index as operation, using this IDBIndexSync as index and the key parameter as key.

This function produces the same result if a record with the given key doesn't exist as when a record exists, but has undefined as value. If you need to tell the two situations apart, you can use openCursor with the same key. This will return a cursor with undefined as value if a record exists, or no cursor if no such record exists.

any key

Key identifying the record to be retrieved. This can also be an IDBKeyRange in which case the function retreives the first existing value in that range.

TransactionInactiveError

The transaction this IDBIndexSync belongs to is not active.

DataError

The key parameter was not passed a valid value.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

any getKey()

If the key parameter is not a valid key or a key range, this method throws a DOMException of type DataError. This method runs the steps for synchronously executing a request and returns the result from that, in this case an index value (a key). The steps are run with the IDBObjectStoreSync associated with this index as source and the steps for retrieving a value from an index as operation, using this IDBIndexSync as index and the key parameter as key.

any key

Key identifying the record to be retrieved. This can also be an IDBKeyRange in which case the function retreives the first existing value in that range.

TransactionInactiveError

The transaction this IDBIndexSync belongs to is not active.

DataError

The key parameter was not passed a valid value.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

unsigned long count()

If the optional key parameter is not a valid key or a key range, this method throws a DOMException of type DataError. This method runs the steps for asynchronously executing a request and returns the IDBRequest created by these steps. The steps are run with this IDBIndex as source and the steps for iterating a cursor as operation, using the created cursor as cursor. If provided, use the key parameter as key, otherwise, use undefined as key. If the result of the algorithm is null return 0 (zero) as the result for the request. Otherwise, use the return cursor to determine the total number of objects that share the key or key range and return that value as the result for the request.

optional any key

Key identifying the record to be retrieved. This can also be an IDBKeyRange.

TransactionInactiveError

The transaction this IDBIndexSync belongs to is not active.

DataError

The key parameter is not a valid key or a key range.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed.

Cursor

Using the synchronous API, an application can process all the records in the cursor's range.

readonly attribute Object source

On getting, returns the IDBObjectStoreSync or IDBIndexSync which this cursor is iterating. This function never returns null or throws an exception, even if the cursor is currently being iterated, has iterated past its end, or its transaction is not active.

readonly attribute DOMString direction

On getting, provide the traversal direction of the cursor.

Returns the cursor's current key. Note that if this property returns an object (specifically an Array), it returns the same object instance every time it is inspected, until the cursor is iterated. This means that if the object is modified, those modifications will be seen by anyone inspecting the value of the cursor. However modifying such an object does not modify the contents of the database.

readonly attribute any primaryKey

Returns the cursor's current effective key. Note that if this property returns an object (specifically an Array), it returns the same object instance every time it is inspected, until the cursor is iterated. This means that if the object is modified, those modifications will be seen by anyone inspecting the value of the cursor. However modifying such an object does not modify the contents of the database.

IDBRequest update()

This method throws a DOMException of type ReadOnlyError if the transaction which this IDBCursorSync belongs to has its mode set to "readonly". If this cursor's got value flag is false or if this cursor was created using openKeyCursor, this method throws a DOMException of type InvalidStateError. If the effective object store of this cursor uses in-line keys and evaluating the key path of the value parameter results in a different value than the cursor's effective key, this method throws DOMException of type DataError.

Otherwise this method creates a structured clone of the value parameter. If the structured clone algorithm throws an exception, that exception is rethrown. Otherwise, run the steps for synchronously executing a request and return the result returned by these steps. The steps are run with this IDBCursorSync as source and the steps for storing a record into an object store as operation, using this cursor's effective object store as store, the created clone as value, this cursor's effective key as key, and with the no-overwrite flag flag set to false.

A result of running the steps for storing a record into an object store is that if the record has been deleted since the cursor moved to it, a new record will be created.

any value

The new value to store at the current position.

TransactionInactiveError

The transaction this IDBCursor belongs to is not active.

ReadOnlyError

The mode of the transaction this IDBCursor belongs to is "readonly"

InvalidStateError

Thrown if cursor was created using openKeyCursor or if the cursor is currently being iterated or has iterated past the end.

DataError

The underlying object store uses in-line keys and the property in value at the object store's key path does not match the key in this cursor's position.

DataCloneError

The data being stored could not be cloned by the internal structured cloning algorithm.

boolean advance()

This method runs the steps for synchronously executing a request. The steps are run with the cursor's source as source. The operation runs the steps for iterating a cursor count number of times with null as key and this cursor as cursor. If the steps for synchronously executing a request returns a cursor, then this function returns true. Otherwise this function returns false.

Before this method returns, unless an exception was thrown, it sets the got value flag in the cursor to false.

Calling this method more than once before new cursor data has been loaded is not allowed and results in a DOMException of type InvalidStateError being thrown. For example, calling advance() twice from the same onsuccess handler results in a DOMException of type InvalidStateError being thrown on the second call.

If the value for count is 0 (zero) or a negative number, this method MUST throw a JavaScript TypeError exception.

[EnforceRange] unsigned long count

The number of advances forward the cursor should make.

TypeError

The value passed into the count parameter was zero or a negative number.

TransactionInactiveError

The transaction this IDBCursorSync belongs to is not active.

InvalidStateError

The cursor is currently being iterated, or has iterated past its end.

boolean continue()

If this cursor's got value flag is false, this method throws a DOMException of type InvalidStateError. If the key parameter is specified and fulfills any of these conditions this method MUST throw a DOMException of type DataError:

• The parameter is not a valid key.
• The parameter is less than or equal to this cursor's position and this cursor's direction is "next" or "nextunique".
• The parameter is greater than or equal to this cursor's position and this cursor's direction is "prev" or "prevunique".

Otherwise this method runs the steps for synchronously executing a request. The steps are run with the cursor's source as source and the steps for iterating a cursor as operation, using the cursor this is called on as cursor and the key parameter as key. If the steps for synchronously executing a request returns a cursor, then this function returns true. Otherwise this function returns false.

Before this method returns, unless an exception was thrown, it sets the got value flag in the cursor to false.

Calling this method more than once before new cursor data has been loaded is not allowed and results in a DOMException of type InvalidStateError being thrown. For example, calling continue() twice from the same onsuccess handler results in a DOMException of type InvalidStateError being thrown on the second call.

optional any key

The next key to position this cursor at

TransactionInactiveError

The transaction this IDBCursorSync belongs to is not active.

InvalidStateError

The cursor is currently being iterated, or has iterated past its end.

DataError

The key parameter was specified but did not contain a valid key.

boolean delete()

This method throws a DOMException of type ReadOnlyError if the transaction which this IDBCursorSync belongs to has its mode set to "readonly". If this cursor's got value flag is false, or if this cursor was created using openKeyCursor a DOMException of type InvalidStateError is thrown.

Otherwise this method runs the steps for synchronously executing a request. The steps are run with this IDBCursorSync as source and the steps for deleting records from an object store as operation, using this cursor's effective object store and effective key as store and key respectively. The function returns the result of running these steps.

TransactionInactiveError

The transaction this IDBCursorSync belongs to is not active.

ReadOnlyError

The mode of the transaction this IDBCursorSync belongs to is "readonly".

InvalidStateError

The cursor was created using openKeyCursor or the cursor is currently being iterated or has iterated past the end.

attribute any value

Returns the cursor's current value. Note that if this property returns an object, it returns the same object instance every time it is inspected, until the cursor is iterated. This means that if the object is modified, those modifications will be seen by anyone inspecting the value of the cursor. However modifying such an object does not modify the contents of the database.

Transaction

When an application creates a transaction synchronously, it blocks until the user agent is able to reserve the required database objects.

readonly attribute DOMString mode

On getting, provide the mode for isolating access to data inside the object stores that are in the scope of the transaction.

attribute IDBDatabaseSync db

The database connection of which this transaction is a part

readonly attribute DOMError error

If this transaction is not finished, is finished but was successfully committed, or was aborted due to a call to the abort function, this property returns null. If this transaction was aborted due to a failed request, this property returns the same DOMError as the request which caused this transaction to be aborted. If this transaction was aborted due to an error when committing the transaction, and not due to a failed request, this property returns a DOMError which contains the reason for the transaction failure (e.g. QuotaExceededError or UnknownError).

IDBObjectStoreSync objectStore()

Returns an IDBObjectStoreSync representing an object store that is within the scope of this transaction. Every call to this function on the same IDBTransactionSync instance and with the same name returns the same IDBObjectStoreSync instance. However the retured IDBObjectStoreSync instance is specific to this IDBTransactionSync. If this function is called on a different IDBTransactionSync, a different IDBObjectStoreSync instance is returned.

DOMString name

The requested object store

NotFoundError

If the requested object store is not in this transaction's scope.

InvalidStateError

Occurs if a request is made on a source object that has been deleted or removed, or if the transaction has finished.

void abort()

If this transaction is finished, throw a DOMException of type InvalidStateError. Otherwise this method sets the transactions's active flag to false and aborts the transaction by running the steps for aborting a transaction with the error parameter set to null.

InvalidStateError

If this transaction has already been committed or aborted.

Once a transaction is aborted or committed, the active transaction on this database connection is removed. A new transaction can be created to perform operations atomically.