IDBObjectStore.createIndex()

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createIndex() 方法在 IDBObjectStore interface creates and returns a new IDBIndex object in the connected database. It creates a new field/column defining a new data point for each database record to contain.

Bear in mind that IndexedDB indexes can contain any JavaScript data type; IndexedDB uses the structured clone algorithm to serialize stored objects, which allows for storage of simple and complex objects.

Note that this method must be called only from a VersionChange transaction mode callback.

注意： 此特征可用于 Web 工作者 .

句法

var myIDBIndex = objectStore.createIndex(indexName, keyPath);
var myIDBIndex = objectStore.createIndex(indexName, keyPath, objectParameters);

参数

indexName
keyPath: The key path for the index to use. Note that it is possible to create an index with an empty keyPath , and also to pass in a sequence (array) as a keyPath .
objectParameters 可选

属性	描述
`unique`	If true, the index will not allow duplicate values for a single key.
`multiEntry`	若 `true` , the index will add an entry in the index for each array element when the keyPath resolves to an Array. If `false` , it will add one single entry containing the Array.
`locale`	Currently Firefox-only (43+), this allows you to specify a locale for the index. Any sorting operations performed on the data via key ranges will then obey sorting rules of that locale (see locale-aware sorting .) You can specify its value in one of three ways: `string` : A string containing a specific locale code, e.g. `en-US` ，或 `pl` . `auto` : The platform default locale will be used (may be changed by user agent settings.) `null or undefined` : If no locale is specified, normal JavaScript sorting will be used — not locale-aware.

返回值

IDBIndex object: the newly created index.

异常

此方法可能引发 DOMException of one of the following types:

异常	描述
`ConstraintError`	Occurs if an index with the same name already exists in the database. Index names are case-sensitive.
`InvalidAccessError`	Occurs if the provided key path is a sequence, and `multiEntry` 被设为 `true` 在 `objectParameters` 对象。
`InvalidStateError`	Occurs if either: The method was not called from a `versionchange` transaction mode callback, i.e. from inside a `IDBOpenDBRequest.onupgradeneeded` handler. The object store has been deleted.
`SyntaxError`	Occurs if the provided `keyPath` 不是 valid key path .
`TransactionInactiveError`	Occurs if the transaction this `IDBObjectStore` belongs to is not active (e.g. has been deleted or removed.) In Firefox previous to version 41, an `InvalidStateError` was raised in this case as well, which was misleading; this has now been fixed (see bug 1176165 )。

范例

In the following example you can see the IDBOpenDBRequest.onupgradeneeded handler being used to update the database structure if a database with a higher version number is loaded. createIndex() is used to create new indexes on the object store. For a full working example, see our 待办通知 app ( 实时查看范例 )。

var db;
// Let us open our database
var DBOpenRequest = window.indexedDB.open("toDoList", 4);
// Two event handlers for opening the database.
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 below.
  db = request.result;
  // Run the displayData() function to populate the task list with
  // all the to-do list data already in the IDB
  displayData();
};
// This handler fires when a new database is created and indicates
// either that one has not been created before, or a new version
// was submitted with window.indexedDB.open(). (See above.)
// It is only implemented in recent browsers.
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
  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 });
};

规范

规范	状态	注释
索引数据库 API 2.0 The definition of 'createIndex()' in that specification.	推荐
索引数据库 API 草案 The definition of 'createIndex()' in that specification.	推荐

浏览器兼容性

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. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`createIndex`	Chrome 24 24 23 — 57 Prefixed Prefixed Implemented with the vendor prefix: webkit	Edge 12	Firefox 16 16 10 — 16 Prefixed Prefixed Implemented with the vendor prefix: moz	IE 部分支持 10	Opera 15	Safari 7	WebView Android Yes Yes ? — 57 Prefixed Prefixed Implemented with the vendor prefix: webkit	Chrome Android 25 25 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 1.5 — 7.0 Prefixed Prefixed Implemented with the vendor prefix: webkit

图例

完整支持
部分支持
要求使用供应商前缀或不同名称。

另请参阅

使用 IndexedDB
开始事务： IDBDatabase
使用事务： IDBTransaction
设置一系列键： IDBKeyRange
检索并使您的数据改变： IDBObjectStore
使用光标： IDBCursor
参考范例：待办通知 ( 实时查看范例 )。

元数据

最后修改： 2020 年 1 月 22 日

IndexedDB API
IDBObjectStore
特性
方法
1. add()
2. clear()
3. count()
4. createIndex()
5. delete()
6. deleteIndex()
7. get()
8. getAll()
9. getAllKeys()
10. getKey()
11. index()
12. openCursor()
13. openKeyCursor()
14. put()
IndexedDB 相关页面

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句法

参数

返回值

异常

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规范

浏览器兼容性

图例

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