IDBDatabase
The IDBDatabase
interface of the IndexedDB API provides a connection to a database; you can use an IDBDatabase
object to open a transaction on your database then create, manipulate, and delete objects (data) in that database. The interface provides the only way to get and manage versions of the database.
Note: This feature is available in Web Workers
Note: Everything you do in IndexedDB always happens in the context of a transaction, representing interactions with data in the database. All objects in IndexedDB — including object stores, indexes, and cursors — are tied to a particular transaction. Thus, you cannot execute commands, access data, or open anything outside of a transaction.
Properties
IDBDatabase.name
Read only-
A
DOMString
that contains the name of the connected database. IDBDatabase.version
Read only-
A 64-bit integer that contains the version of the connected database. When a database is first created, this attribute is an empty string.
IDBDatabase.objectStoreNames
Read only-
A
DOMStringList
that contains a list of the names of the object stores currently in the connected database.
Methods
Inherits from: EventTarget
IDBDatabase.close()
-
Returns immediately and closes the connection to a database in a separate thread.
IDBDatabase.createMutableFile()
-
Creates a file handle, allowing files to be stored inside an IndexedDB database.
IDBDatabase.createObjectStore()
-
Creates and returns a new object store or index.
IDBDatabase.deleteObjectStore()
-
Destroys the object store with the given name in the connected database, along with any indexes that reference it.
IDBDatabase.transaction()
-
Immediately returns a transaction object (
IDBTransaction
) containing theIDBTransaction.objectStore
method, which you can use to access your object store. Runs in a separate thread.
Events
Listen to these events using addEventListener()
or by assigning an event listener to the oneventname
property of this interface.
close
-
An event fired when the database connection is unexpectedly closed.
versionchange
-
An event fired when a database structure change was requested.
The following events are available to IDBDatabase
via event bubbling from IDBTransaction
:
Example
In the following code snippet, we open a database asynchronously (IDBFactory
), handle success and error cases, and create a new object store in the case that an upgrade is needed (IDBdatabase
). For a complete working example, see our To-do Notifications app (view example live.)
// Let us open our database
var DBOpenRequest = window.indexedDB.open("toDoList", 4);
// these two event handlers act on the IDBDatabase object,
// when the database is opened successfully, or not
DBOpenRequest.onerror = event => { note.innerHTML += '<li>Error loading database.</li>'; };
DBOpenRequest.onsuccess = event => {
note.innerHTML += '<li>Database initialized.</li>';
// store the result of opening the database in the db
// variable. This is used a lot later on
db = DBOpenRequest.result;
// Run the displayData() function to populate the task
// list with all the to-do list data already in the IDB
displayData();
};
// This event handles the event whereby a new version of
// the database needs to be created Either one has not
// been created before, or a new version number has been
// submitted via the window.indexedDB.open line above
DBOpenRequest.onupgradeneeded = event => {
var db = event.target.result;
db.onerror = function(event) {
note.innerHTML += '<li>Error loading database.</li>';
};
// Create an objectStore for this database using
// IDBDatabase.createObjectStore
var objectStore = db.createObjectStore("toDoList", { keyPath: "taskTitle" });
// define what data items the objectStore will contain
objectStore.createIndex("hours", "hours", { unique: false });
objectStore.createIndex("minutes", "minutes", { unique: false });
objectStore.createIndex("day", "day", { unique: false });
objectStore.createIndex("month", "month", { unique: false });
objectStore.createIndex("year", "year", { unique: false });
objectStore.createIndex("notified", "notified", { unique: false });
note.innerHTML += '<li>Object store created.</li>';
};
This next line opens up a transaction on the Database, then opens an object store that we can then manipulate the data inside of.
var objectStore = db.transaction('toDoList', 'readwrite').objectStore('toDoList');
Specifications
Specification |
---|
Indexed Database API 3.0 # database-interface |
Browser compatibility
BCD tables only load in the browser
See also
- Using IndexedDB
- Starting transactions:
IDBDatabase
- Using transactions:
IDBTransaction
- Setting a range of keys:
IDBKeyRange
- Retrieving and making changes to your data:
IDBObjectStore
- Using cursors:
IDBCursor
- Reference example: To-do Notifications (view example live.)