第十五部分：附录

// 打开数据库
IDBFactory.open(name, version)
 
// 删除数据库
IDBFactory.deleteDatabase(name)
 
// 比较两个键
IDBFactory.cmp(first, second)

// 属性
db.name        // 数据库名称
db.version     // 数据库版本
db.objectStoreNames  // 对象存储列表
 
// 方法
db.createObjectStore(name, options)
db.deleteObjectStore(name)
db.transaction(storeNames, mode)
db.close()

// 属性
transaction.db          // 关联的数据库
transaction.mode        // 事务模式
transaction.objectStoreNames  // 涉及的对象存储
 
// 方法
transaction.objectStore(name)
transaction.abort()

// 属性
store.name
store.keyPath
store.autoIncrement
store.indexNames
 
// 方法
store.add(value, key)
store.put(value, key)
store.delete(key)
store.get(key)
store.getAll(query, count)
store.getKey(key)
store.clear()
store.count(query)
store.openCursor(query, direction)
store.openKeyCursor(query, direction)
store.createIndex(name, keyPath, options)
store.deleteIndex(name)
store.index(name)

文档：

• MDN IndexedDB 文档
• W3C IndexedDB 规范

库：

• idb：轻量级 Promise 封装
• Dexie.js：功能丰富的 ORM 风格封装
• localForage：类似 LocalStorage 的 API

// 完整的 IndexedDB 封装类
class IndexedDBManager {
  constructor(dbName, version) {
    this.dbName = dbName;
    this.version = version;
    this.db = null;
  }
 
  async open(schema) {
    return new Promise((resolve, reject) => {
      const request = indexedDB.open(this.dbName, this.version);
 
      request.onupgradeneeded = (event) => {
        const db = event.target.result;
        schema(db, event.target.transaction);
      };
 
      request.onsuccess = (event) => {
        this.db = event.target.result;
        resolve(this.db);
      };
 
      request.onerror = (event) => reject(event.target.error);
    });
  }
 
  async add(storeName, data) {
    const tx = this.db.transaction([storeName], 'readwrite');
    const store = tx.objectStore(storeName);
    return new Promise((resolve, reject) => {
      const request = store.add(data);
      request.onsuccess = () => resolve(request.result);
      request.onerror = () => reject(request.error);
    });
  }
 
  async get(storeName, key) {
    const tx = this.db.transaction([storeName], 'readonly');
    const store = tx.objectStore(storeName);
    return new Promise((resolve, reject) => {
      const request = store.get(key);
      request.onsuccess = () => resolve(request.result);
      request.onerror = () => reject(request.error);
    });
  }
 
  async put(storeName, data) {
    const tx = this.db.transaction([storeName], 'readwrite');
    const store = tx.objectStore(storeName);
    return new Promise((resolve, reject) => {
      const request = store.put(data);
      request.onsuccess = () => resolve(request.result);
      request.onerror = () => reject(request.error);
    });
  }
 
  async delete(storeName, key) {
    const tx = this.db.transaction([storeName], 'readwrite');
    const store = tx.objectStore(storeName);
    return new Promise((resolve, reject) => {
      const request = store.delete(key);
      request.onsuccess = () => resolve();
      request.onerror = () => reject(request.error);
    });
  }
 
  async getAll(storeName, query, count) {
    const tx = this.db.transaction([storeName], 'readonly');
    const store = tx.objectStore(storeName);
    return new Promise((resolve, reject) => {
      const request = store.getAll(query, count);
      request.onsuccess = () => resolve(request.result);
      request.onerror = () => reject(request.error);
    });
  }
 
  async clear(storeName) {
    const tx = this.db.transaction([storeName], 'readwrite');
    const store = tx.objectStore(storeName);
    return new Promise((resolve, reject) => {
      const request = store.clear();
      request.onsuccess = () => resolve();
      request.onerror = () => reject(request.error);
    });
  }
 
  close() {
    if (this.db) {
      this.db.close();
      this.db = null;
    }
  }
}
 
// 使用示例
const dbManager = new IndexedDBManager('MyApp', 1);
 
await dbManager.open((db, tx) => {
  if (!db.objectStoreNames.contains('users')) {
    const store = db.createObjectStore('users', { keyPath: 'id' });
    store.createIndex('emailIndex', 'email', { unique: true });
  }
});
 
// CRUD 操作
const userId = await dbManager.add('users', {
  id: 1,
  name: '张三',
  email: 'zhangsan@example.com'
});
 
const user = await dbManager.get('users', 1);
await dbManager.put('users', { ...user, age: 25 });
await dbManager.delete('users', 1);
 
dbManager.close();

本教程从基础概念到高级应用，从理论到实战，全面介绍了 IndexedDB 的使用方法。希望读者通过本教程能够：

• 理解 IndexedDB 的设计思想和核心概念
• 熟练进行数据库设计和索引优化
• 处理复杂的事务和并发场景
• 构建高性能的离线 Web 应用

IndexedDB 是 Web 平台强大的客户端存储方案，随着 PWA 和离线应用的发展，它的重要性将越来越高。持续学习和实践，才能充分发挥其潜力。

如果你发现错误或希望补充内容，欢迎通过以下方式反馈。

—

本教程完。