IDBTransaction：错误事件

当请求返回错误时，error 事件将在 IDBTransaction 上触发，并且该事件会冒泡到事务对象。

注意： 要处理事务失败的所有方式，请考虑改为侦听 abort 事件。

语法

在诸如 addEventListener() 之类的方法中使用事件名称，或设置事件处理程序属性。

addEventListener("error", (event) => {});
onerror = (event) => {};

事件类型

一个通用的 Event。

冒泡

此事件冒泡到 IDBDatabase。event.target 属性引用冒泡的 IDBTransaction 对象。

有关更多信息，请参阅事件冒泡。

示例

此示例打开一个数据库并尝试添加记录，侦听 add() 操作的 error 事件（例如，如果具有给定 taskTitle 的记录已存在，则会发生这种情况）

// Open the database
const dBOpenRequest = window.indexedDB.open("toDoList", 4);

dBOpenRequest.onupgradeneeded = (event) => {
  const db = event.target.result;

  // Create an objectStore for this database
  const 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 });
};

dBOpenRequest.onsuccess = (event) => {
  const db = dBOpenRequest.result;

  // open a read/write db transaction, ready for adding the data
  const transaction = db.transaction(["toDoList"], "readwrite");

  transaction.addEventListener("error", () => {
    console.log(`Error adding new item: ${newItem.taskTitle}`);
  });

  const objectStore = transaction.objectStore("toDoList");
  const newItem = {
    taskTitle: "my task",
    hours: 10,
    minutes: 10,
    day: 10,
    month: "January",
    year: 2020,
  };

  const objectStoreRequest = objectStore.add(newItem);
};

相同的示例，使用 onerror 属性而不是 addEventListener()

// Open the database
const dBOpenRequest = window.indexedDB.open("toDoList", 4);

dBOpenRequest.onupgradeneeded = (event) => {
  const db = event.target.result;

  // Create an objectStore for this database
  const 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 });
};

dBOpenRequest.onsuccess = (event) => {
  const db = dBOpenRequest.result;

  // open a read/write db transaction, ready for adding the data
  const transaction = db.transaction(["toDoList"], "readwrite");

  transaction.onerror = () => {
    console.log(`Error adding new item: ${newItem.taskTitle}`);
  };

  const objectStore = transaction.objectStore("toDoList");
  const newItem = {
    taskTitle: "my task",
    hours: 10,
    minutes: 10,
    day: 10,
    month: "January",
    year: 2020,
  };

  const objectStoreRequest = objectStore.add(newItem);
};

浏览器兼容性

BCD 表仅在启用 JavaScript 的浏览器中加载。

另请参阅

使用 IndexedDB