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.

Nota: Esta característica está disponible en 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.

Methods

Inherits from: EventTarget

IDBDatabase.close() (en-US)
Returns immediately and closes the connection to a database in a separate thread.
IDBDatabase.createObjectStore() (en-US)
Creates and returns a new object store or index.
IDBDatabase.deleteObjectStore() (en-US)
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 (en-US)) containing the IDBTransaction.objectStore (en-US) method, which you can use to access your object store. Runs in a separate thread.

Properties

IDBDatabase.name (en-US) Read only
A DOMString that contains the name of the connected database.
IDBDatabase.version (en-US) 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 (en-US) Read only
A DOMStringList (en-US) that contains a list of the names of the object stores currently in the connected database.

Event handlers

IDBDatabase.onabort (en-US)
Fires when access of the database is aborted.
IDBDatabase.onclose (en-US)
Fires when the close event occurs; this happens when the database is unexpectedly closed, such as during application shutdown.
IDBDatabase.onerror (en-US)
Fires when access to the database fails.
IDBDatabase.onversionchange (en-US)

Fires when a database structure change (IDBOpenDBRequest.onupgradeneeded (en-US) event or IDBFactory.deleteDatabase() (en-US) was requested elsewhere (most probably in another window/tab on the same computer). This is different from the version change transaction (see IDBVersionChangeEvent (en-US)), but it is related.

Example

In the following code snippet, we open a database asynchronously (IDBFactory (en-US)), 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 = function(event) {
    note.innerHTML += '<li>Error loading database.</li>';
  };

  DBOpenRequest.onsuccess = function(event) {
    note.innerHTML += '<li>Database initialised.</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 = function(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').objectStore('toDoList'); 

Specifications

Browser compatibility

BCD tables only load in the browser

See also