在此页

• 句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

primaryKey 只读特性在 IDBCursor interface returns the cursor's current effective key. If the cursor is currently being iterated or has iterated outside its range, this is set to undefined. The cursor's primary key can be any data type.

注意： 此特征可用于 Web 工作者 .

句法

var value = cursor.primaryKey;
					

值

A value of any data type.

范例

In this simple fragment we create a transaction, retrieve an object store, then use a cursor to iterate through all the records in the object store. Within each iteration we log the primary key of the cursor to the console, something like this (its the album title in each case, which is our primarykey):

Hemispheres
					

T he cursor does not require us to select the data based on a key; we can just grab all of it. Also note that in each iteration of the loop, you can grab data from the current record under the cursor object using cursor.value.foo . For a complete working example, see our IDBCursor example ( 实时查看范例 )。

function displayData() {
  var transaction = db.transaction(['rushAlbumList'], "readonly");
  var objectStore = transaction.objectStore('rushAlbumList');
  objectStore.openCursor().onsuccess = function(event) {
    var cursor = event.target.result;
    if(cursor) {
      var listItem = document.createElement('li');
      listItem.innerHTML = cursor.value.albumTitle + ', ' + cursor.value.year;
      list.appendChild(listItem);
      console.log(cursor.primaryKey);
      cursor.continue();
    } else {
      console.log('Entries all displayed.');
    }
  };
};
					

规范

规范	状态	注释
索引数据库 API 2.0 The definition of 'primaryKey' in that specification.	推荐
索引数据库 API 草案 The definition of 'primaryKey' 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
primaryKey	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	Chrome Android Yes	Firefox Android 22	Opera Android 14	Safari iOS 8	Samsung Internet Android Yes

图例

完整支持

完整支持

部分支持

部分支持

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

• 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

相关话题

1. IDBCursor
2. 特性

   1. direction
   2. key
   3. primaryKey
   4. request
   5. source
3. 方法

   1. advance()
   2. continue()
   3. continuePrimaryKey()
   4. delete()
   5. update()