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 .

注意: 此特征可用于 Web 工作者 .

特性

IDBIndex.isAutoLocale 只读
返回 Boolean indicating whether the index had a locale value of auto specified upon its creation (see createIndex() 's optionalParameters .)
IDBIndex.locale 只读
Returns the locale of the index (for example en-US ,或 pl ) if it had a locale value specified upon its creation (see createIndex() 's optionalParameters .)
IDBIndex.name
The name of this index.
IDBIndex.objectStore 只读
The name of the object store referenced by this index.
IDBIndex.keyPath 只读
key path of this index. If null, this index is not auto-populated .
IDBIndex.multiEntry 只读
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 只读
true , this index does not allow duplicate values for a key.

方法

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.

范例

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 使用 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.');
    }
  };
};
					

规范

规范 状态 Comment
Indexed Database API 2.0
The definition of 'IDBIndex' in that specification.
Recommendation
Indexed Database API Draft
The definition of 'IDBIndex' in that specification.
Recommendation

浏览器兼容性

更新 GitHub 上的兼容性数据
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 24
24
不支持 23 — 57
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 16
16
不支持 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
IE 部分支持 10 Opera 15 Safari 7 WebView Android Yes
Yes
不支持 ? — 57
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android 25
25
不支持 25 — 57
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Firefox Android 22 Opera Android 14 Safari iOS 8 Samsung Internet Android 1.5
1.5
不支持 1.5 — 7.0
Prefixed
Prefixed Implemented with the vendor prefix: webkit
count Chrome 24
24
不支持 23 — 24
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 16
16
不支持 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
IE 部分支持 10 Opera 15 Safari 7 WebView Android Yes
Yes
不支持 ? — ?
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android 25 Firefox Android 22 Opera Android 14 Safari iOS 8 Samsung Internet Android 1.5
get Chrome 24
24
不支持 23 — 24
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 16
16
不支持 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
IE 部分支持 10 Opera 15 Safari 7 WebView Android Yes
Yes
不支持 ? — ?
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android 25 Firefox Android 22 Opera Android 14 Safari iOS 8 Samsung Internet Android 1.5
getAll Chrome 48 Edge ≤18 Firefox 44 IE No Opera 35 Safari 10.1 WebView Android 48 Chrome Android 48 Firefox Android 44 Opera Android 35 Safari iOS 10.3 Samsung Internet Android 5.0
getAllKeys Chrome 48 Edge ≤18 Firefox 44
Disabled
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 Opera 35 Safari 10.1 WebView Android 48 Chrome Android 48 Firefox Android 44
Disabled
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 35 Safari iOS 10.3 Samsung Internet Android 5.0
getKey Chrome 24
24
不支持 23 — 24
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 16
16
不支持 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
IE 部分支持 10 Opera 15 Safari 7 WebView Android Yes
Yes
不支持 ? — ?
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android 25 Firefox Android 22 Opera Android 14 Safari iOS 8 Samsung Internet Android 1.5
isAutoLocale
非标
Chrome No Edge No Firefox 43 IE No Opera No Safari No WebView Android No Chrome Android No Firefox Android 43 Opera Android No Safari iOS No Samsung Internet Android No
keyPath Chrome 24
24
不支持 23 — 24
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 16
16
不支持 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
IE 部分支持 10 Opera 15 Safari 7 WebView Android Yes
Yes
不支持 ? — ?
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android 25 Firefox Android 22 Opera Android 14 Safari iOS 8 Samsung Internet Android 1.5
locale
非标
Chrome No Edge No Firefox 43 IE No Opera No Safari No WebView Android No Chrome Android No Firefox Android 43 Opera Android No Safari iOS No Samsung Internet Android No
multiEntry Chrome 24
24
不支持 23 — 24
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 16
16
不支持 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
IE 部分支持 10 Opera 15 Safari 7 WebView Android Yes
Yes
不支持 ? — ?
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android 25 Firefox Android 22 Opera Android 14 Safari iOS 8 Samsung Internet Android 1.5
name Chrome 24
24
不支持 23 — 24
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 16
16
不支持 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
IE 部分支持 10 Opera 15 Safari 7 WebView Android Yes
Yes
不支持 ? — ?
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android 25 Firefox Android 22 Opera Android 14 Safari iOS 8 Samsung Internet Android 1.5
objectStore Chrome 24
24
不支持 23 — 24
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 16
16
不支持 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
IE 部分支持 10 Opera 15 Safari 7 WebView Android Yes
Yes
不支持 ? — ?
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android 25 Firefox Android 22 Opera Android 14 Safari iOS 8 Samsung Internet Android 1.5
openCursor Chrome 24
24
不支持 23 — 24
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 16
16
不支持 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
IE 部分支持 10 Opera 15 Safari 7 WebView Android Yes
Yes
不支持 ? — ?
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android 25 Firefox Android 22 Opera Android 14 Safari iOS 8 Samsung Internet Android 1.5
openKeyCursor Chrome 24
24
不支持 23 — 24
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 16
16
不支持 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
IE 部分支持 10 Opera 15 Safari 7 WebView Android Yes
Yes
不支持 ? — ?
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android 25 Firefox Android 22 Opera Android 14 Safari iOS 8 Samsung Internet Android 1.5
unique Chrome 24
24
不支持 23 — 24
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge 12 Firefox 16
16
不支持 10 — 16
Prefixed
Prefixed Implemented with the vendor prefix: moz
IE 部分支持 10 Opera 15 Safari 7 WebView Android Yes
Yes
不支持 ? — ?
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Chrome Android 25 Firefox Android 22 Opera Android 14 Safari iOS 8 Samsung Internet Android 1.5
Available in workers Chrome Yes Edge ≤18 Firefox 37 IE ? Opera Yes Safari ? WebView Android Yes Chrome Android Yes Firefox Android 37 Opera Android Yes Safari iOS ? Samsung Internet Android Yes

图例

完整支持
完整支持
部分支持
部分支持
不支持
不支持
兼容性未知
兼容性未知
实验。期望将来行为有所改变。
实验。期望将来行为有所改变。
非标。预期跨浏览器支持较差。
非标。预期跨浏览器支持较差。
用户必须明确启用此特征。
用户必须明确启用此特征。
要求使用供应商前缀或不同名称。
要求使用供应商前缀或不同名称。

另请参阅