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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 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
The definition of 'IDBIndex' in that specification.
Recommendation  
Indexed Database API 2.0
The definition of 'IDBIndex' in that specification.
Recommendation  

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic supportChrome Full support 24
Full support 24
No support 23 — 57
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support YesFirefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — 57
Prefixed
Prefixed Requires the vendor prefix: webkit
Chrome Android Full support 25
Full support 25
No support 25 — 57
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Mobile ? Firefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes
Full support Yes
No support ? — 7.0
Prefixed
Prefixed Requires the vendor prefix: webkit
Available in workersChrome Full support YesEdge Full support YesFirefox Full support 37IE ? Opera Full support YesSafari ? WebView Android Full support YesChrome Android Full support YesEdge Mobile Full support YesFirefox Android Full support 37Opera Android Full support YesSafari iOS ? Samsung Internet Android Full support Yes
isAutoLocale
ExperimentalNon-standard
Chrome No support NoEdge No support NoFirefox Full support 43IE No support NoOpera No support NoSafari No support NoWebView Android No support NoChrome Android No support NoEdge Mobile No support NoFirefox Android Full support 43Opera Android No support NoSafari iOS No support NoSamsung Internet Android No support No
keyPathChrome Full support 24
Full support 24
No support 23 — 24
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support 12Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — ?
Prefixed
Prefixed Requires the vendor prefix: webkit
Chrome Android Full support 25Edge Mobile Full support YesFirefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes
locale
ExperimentalNon-standard
Chrome No support NoEdge No support NoFirefox Full support 43IE No support NoOpera No support NoSafari No support NoWebView Android No support NoChrome Android No support NoEdge Mobile No support NoFirefox Android Full support 43Opera Android No support NoSafari iOS No support NoSamsung Internet Android No support No
multiEntryChrome Full support 24
Full support 24
No support 23 — 24
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge ? Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — ?
Prefixed
Prefixed Requires the vendor prefix: webkit
Chrome Android Full support 25Edge Mobile ? Firefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes
nameChrome Full support 24
Full support 24
No support 23 — 24
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support 12Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — ?
Prefixed
Prefixed Requires the vendor prefix: webkit
Chrome Android Full support 25Edge Mobile Full support YesFirefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes
objectStoreChrome Full support 24
Full support 24
No support 23 — 24
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support 12Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — ?
Prefixed
Prefixed Requires the vendor prefix: webkit
Chrome Android Full support 25Edge Mobile Full support YesFirefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes
uniqueChrome Full support 24
Full support 24
No support 23 — 24
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support 12Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — ?
Prefixed
Prefixed Requires the vendor prefix: webkit
Chrome Android Full support 25Edge Mobile Full support YesFirefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes
countChrome Full support 24
Full support 24
No support 23 — 24
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support 12Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — ?
Prefixed
Prefixed Requires the vendor prefix: webkit
Chrome Android Full support 25Edge Mobile Full support YesFirefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes
getChrome Full support 24
Full support 24
No support 23 — 24
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support 12Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — ?
Prefixed
Prefixed Requires the vendor prefix: webkit
Chrome Android Full support 25Edge Mobile Full support YesFirefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes
getAllChrome Full support 48Edge Full support YesFirefox 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 NoOpera Full support 35Safari Full support 10.1WebView Android Full support 48Chrome Android Full support 48Edge Mobile Full support YesFirefox 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 35Safari iOS Full support 10.1Samsung Internet Android Full support 5.0
getAllKeysChrome Full support 48Edge Full support YesFirefox 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 NoOpera Full support 35Safari Full support 10.1WebView Android Full support 48Chrome Android Full support 48Edge Mobile Full support YesFirefox 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 35Safari iOS Full support 10.1Samsung Internet Android Full support 5.0
getKeyChrome Full support 24
Full support 24
No support 23 — 24
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support 12Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — ?
Prefixed
Prefixed Requires the vendor prefix: webkit
Chrome Android Full support 25Edge Mobile Full support YesFirefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes
openCursorChrome Full support 24
Full support 24
No support 23 — 24
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support 12Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — ?
Prefixed
Prefixed Requires the vendor prefix: webkit
Chrome Android Full support 25Edge Mobile Full support YesFirefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes
openKeyCursorChrome Full support 24
Full support 24
No support 23 — 24
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support 12Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support Yes
Full support Yes
No support ? — ?
Prefixed
Prefixed Requires the vendor prefix: webkit
Chrome Android Full support 25Edge Mobile Full support YesFirefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes

Legend

Full support  
Full 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.
See implementation notes.
See implementation notes.
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

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