IDBObjectStore: keyPath 属性
注意: 此功能在 Web Workers 中可用。
keyPath
是 IDBObjectStore
接口的只读属性,它返回此对象存储的 键路径。
如果此属性为 null,则应用程序必须为每个修改操作提供一个键。
值
任何值类型。
示例
在以下代码片段中,我们对数据库打开了一个读写事务,并使用 add()
向对象存储中添加了一些数据。对象存储创建完成后,我们向控制台输出 objectStore.keyPath
。有关完整的示例,请参阅我们的 待办通知 应用程序 (查看实时示例)。
js
// Let us open our database
const DBOpenRequest = window.indexedDB.open("toDoList", 4);
DBOpenRequest.onsuccess = (event) => {
note.appendChild(document.createElement("li")).textContent =
"Database initialized.";
// store the result of opening the database in the db variable.
// This is used a lot below
db = DBOpenRequest.result;
// Run the addData() function to add the data to the database
addData();
};
function addData() {
// Create a new object ready to insert into the IDB
const newItem = [
{
taskTitle: "Walk dog",
hours: 19,
minutes: 30,
day: 24,
month: "December",
year: 2013,
notified: "no",
},
];
// open a read/write db transaction, ready for adding the data
const transaction = db.transaction(["toDoList"], "readwrite");
// report on the success of the transaction completing, when everything is done
transaction.oncomplete = (event) => {
note.appendChild(document.createElement("li")).textContent =
"Transaction completed.";
};
transaction.onerror = (event) => {
note.appendChild(document.createElement("li")).textContent =
"Transaction not opened due to error. Duplicate items not allowed.";
};
// create an object store on the transaction
const objectStore = transaction.objectStore("toDoList");
console.log(objectStore.keyPath);
// Make a request to add our newItem object to the object store
const objectStoreRequest = objectStore.add(newItem[0]);
objectStoreRequest.onsuccess = (event) => {
// report the success of our request
note.appendChild(document.createElement("li")).textContent =
"Request successful.";
};
}
规范
规范 |
---|
Indexed Database API 3.0 # ref-for-dom-idbobjectstore-keypath① |
浏览器兼容性
BCD 表格仅在启用 JavaScript 的浏览器中加载。
另请参阅
- 使用 IndexedDB
- 启动事务:
IDBDatabase
- 使用事务:
IDBTransaction
- 设置键范围:
IDBKeyRange
- 检索和修改您的数据:
IDBObjectStore
- 使用游标:
IDBCursor
- 参考示例: 待办通知 (查看实时示例)。