IDBObjectStore.clear()

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clear() 方法在 IDBObjectStore interface creates and immediately returns an IDBRequest object, and clears this object store in a separate thread. This is for deleting all the current data out of an object store.

Clearing an object store consists of removing all records from the object store and removing all records in indexes that reference the object store. To remove only some of the records in a store, use IDBObjectStore.delete passing a key or IDBKeyRange .

注意： 此特征可用于 Web 工作者 .

句法

var request = objectStore.clear();

IDBRequest object on which subsequent events related to this operation are fired.

异常

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

异常	描述
`ReadOnlyError`	The transaction associated with this operation is in read-only mode .
`TransactionInactiveError`	This `IDBObjectStore` 's transaction is inactive.

范例

In the following code snippet, we open a read/write transaction on our database and clear all the current data out of the object store using clear() . For a full working example, see our 待办通知 app ( 实时查看范例 )。

// Let us open our database
var DBOpenRequest = window.indexedDB.open("toDoList", 4);
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 = DBOpenRequest.result;
  // Clear all the data form the object store
  clearData();
};
function clearData() {
  // open a read/write db transaction, ready for clearing the data
  var transaction = db.transaction(["toDoList"], "readwrite");
  // report on the success of the transaction completing, when everything is done
  transaction.oncomplete = function(event) {
    note.innerHTML += '<li>Transaction completed.</li>';
  };
  transaction.onerror = function(event) {
    note.innerHTML += '<li>Transaction not opened due to error: ' + transaction.error + '</li>';
  };
  // create an object store on the transaction
  var objectStore = transaction.objectStore("toDoList");
  // Make a request to clear all the data out of the object store
  var objectStoreRequest = objectStore.clear();
  objectStoreRequest.onsuccess = function(event) {
    // report the success of our request
    note.innerHTML += '<li>Request successful.</li>';
  };
};

规范

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