Web/API/IDBIndex

IDBIndex interface of the IndexedDB API provides asynchronous access to an index in a database. An index is a kind of object store for looking up records in another object store, called the referenced object store. You use this interface to retrieve data.

You can retrieve records in an object store through the primary key or by using an index. An index lets you look up records in an object store using properties of the values in the object stores records other than the primary key

The index is a persistent key-value storage where the value part of its records is the key part of a record in the referenced object store. The records in an index are automatically populated whenever records in the referenced object store are inserted, updated, or deleted. Each record in an index can point to only one record in its referenced object store, but several indexes can reference the same object store. When the object store changes, all indexes that refers to the object store are automatically updated.

You can grab a set of keys within a range. To learn more, see IDBKeyRange.

Note: This feature is available in Web Workers.

Properties

IDBIndex.isAutoLocale Read only '

Returns a Boolean indicating whether the index had a locale value of auto specified upon its creation (see createIndex()'s optionalParameters.)

IDBIndex.locale Read only '

Returns the locale of the index (for example en-US, or pl) if it had a locale value specified upon its creation (see createIndex()'s optionalParameters.)

IDBIndex.name

The name of this index.

IDBIndex.objectStore Read only

The name of the object store referenced by this index.

IDBIndex.keyPath Read only

The key path of this index. If null, this index is not auto-populated.

IDBIndex.multiEntry Read only

Affects how the index behaves when the result of evaluating the index's key path yields an array. If true, there is one record in the index for each item in an array of keys. If false, then there is one record for each key that is an array.

IDBIndex.unique Read only

If true, this index does not allow duplicate values for a key.

Methods

Inherits from: EventTarget

IDBIndex.count()

Returns an IDBRequest object, and in a separate thread, returns the number of records within a key range.

IDBIndex.get()

Returns an IDBRequest object, and, in a separate thread, finds either the value in the referenced object store that corresponds to the given key or the first corresponding value, if key is an IDBKeyRange.

IDBIndex.getKey()

Returns an IDBRequest object, and, in a separate thread, finds either the given key or the primary key, if key is an IDBKeyRange.

IDBIndex.getAll()

Returns an IDBRequest object, in a separate thread, finds all matching values in the referenced object store that correspond to the given key or are in range, if key is an IDBKeyRange.

IDBIndex.getAllKeys()

Returns an IDBRequest object, in a separate thread, finds all matching keys in the referenced object store that correspond to the given key or are in range, if key is an IDBKeyRange.

IDBIndex.openCursor()

Returns an IDBRequest object, and, in a separate thread, creates a cursor over the specified key range.

IDBIndex.openKeyCursor()

Returns an IDBRequest object, and, in a separate thread, creates a cursor over the specified key range, as arranged by this index.

Example

In the following example we open a transaction and an object store, then get the index lName from a simple contacts database. We then open a basic cursor on the index using IDBIndex.openCursor — this works the same as opening a cursor directly on an ObjectStore using IDBObjectStore.openCursor except that the returned records are sorted based on the index, not the primary key.

Finally, we iterate through each record, and insert the data into an HTML table. For a complete working example, see our [[../../../../../../mdn.github.io/indexeddb-examples/idbindex/index|IDBIndex-example demo repo]] (View the example live.)

function displayDataByIndex() {
  tableEntry.innerHTML = '';
  var transaction = db.transaction(['contactsList'], 'readonly');
  var objectStore = transaction.objectStore('contactsList');

  var myIndex = objectStore.index('lName'); 
  myIndex.openCursor().onsuccess = function(event) {
    var cursor = event.target.result;
    if(cursor) {
      var tableRow = document.createElement('tr');
      tableRow.innerHTML =   '<td>' + cursor.value.id + '</td>'
                           + '<td>' + cursor.value.lName + '</td>'
                           + '<td>' + cursor.value.fName + '</td>'
                           + '<td>' + cursor.value.jTitle + '</td>'
                           + '<td>' + cursor.value.company + '</td>'
                           + '<td>' + cursor.value.eMail + '</td>'
                           + '<td>' + cursor.value.phone + '</td>'
                           + '<td>' + cursor.value.age + '</td>';
      tableEntry.appendChild(tableRow);  

      cursor.continue();
    } else {
      console.log('Entries all displayed.');    
    }
  };
};

Specification

Specification	Status	Comment
Indexed Database API 2.0The definition of 'IDBIndex' in that specification.	Recommendation
Indexed Database API DraftThe definition of 'IDBIndex' in that specification.	Recommendation

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
IDBIndex	Chrome Full support 24 Full support 24 No support 23 — 57 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — 57 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25 Full support 25 No support 25 — 57 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support 1.5 Full support 1.5 No support 1.5 — 7.0 Prefixed' Prefixed' Implemented with the vendor prefix: webkit
count	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — ? Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support 1.5
get	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — ? Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support 1.5
getAll	Chrome Full support 48	Edge Full support ≤18	Firefox Full support 44	IE No support No	Opera Full support 35	Safari Full support 10.1	WebView Android Full support 48	Chrome Android Full support 48	Firefox Android Full support 44	Opera Android Full support 35	Safari iOS Full support 10.3	Samsung Internet Android Full support 5.0
getAllKeys	Chrome Full support 48	Edge Full support ≤18	Firefox Full support 44 Disabled' Full support 44 Disabled' Disabled' From version 44: this feature is behind the dom.indexedDB.experimental preference. To change preferences in Firefox, visit about:config.	IE No support No	Opera Full support 35	Safari Full support 10.1	WebView Android Full support 48	Chrome Android Full support 48	Firefox Android Full support 44 Disabled' Full support 44 Disabled' Disabled' From version 44: this feature is behind the dom.indexedDB.experimental preference. To change preferences in Firefox, visit about:config.	Opera Android Full support 35	Safari iOS Full support 10.3	Samsung Internet Android Full support 5.0
getKey	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — ? Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support 1.5
isAutoLocale Experimental'Non-standard'	Chrome No support No	Edge No support No	Firefox Full support 43	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 43	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No
keyPath	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — ? Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support 1.5
locale Experimental'Non-standard'	Chrome No support No	Edge No support No	Firefox Full support 43	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 43	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No
multiEntry	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — ? Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support 1.5
name	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — ? Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support 1.5
objectStore	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — ? Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support 1.5
openCursor	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — ? Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support 1.5
openKeyCursor	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — ? Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support 1.5
unique	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — ? Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support 1.5
Available in workers	Chrome Full support Yes	Edge Full support ≤18	Firefox Full support 37	IE ?	Opera Full support Yes	Safari ?	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 37	Opera Android Full support Yes	Safari iOS ?	Samsung Internet Android Full support Yes

Legend

Full support  

Full support

Partial support  

Partial support

No support  

No support

Compatibility unknown  

Compatibility unknown

Experimental. Expect behavior to change in the future.'

Experimental. Expect behavior to change in the future.

Non-standard. Expect poor cross-browser support.'

Non-standard. Expect poor cross-browser support.

User must explicitly enable this feature.'

User must explicitly enable this feature.

Requires a vendor prefix or different name for use.'

Requires a vendor prefix or different name for use.

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 ([[../../../../../../mdn.github.io/to-do-notifications/index|view example live]].)

IDBIndex by Mozilla Contributors is licensed under CC-BY-SA 2.5.