JavaScript数据库_IndexedDB离线存储方案

let request = indexedDB.open('MyAppDB', 1);
request.onupgradeneeded = function(event) {
  let db = event.target.result;
  if (!db.objectStoreNames.contains('users')) {
    db.createObjectStore('users', { keyPath: 'id' });
  }
};
request.onsuccess = function(event) {
  let db = event.target.result;
  // 数据库打开成功，可进行增删改查
};

let store = db.createObjectStore('users', { keyPath: 'id' });
store.createIndex('name', 'name', { unique: false });
store.createIndex('email', 'email', { unique: true });

let transaction = db.transaction(['users'], 'readwrite');
let store = transaction.objectStore('users');
let addUser = store.add({ id: 1, name: '张三', email: 'zhang@example.com' });

addUser.onsuccess = () => console.log('添加成功');
addUser.onerror = () => console.error('添加失败');

let getRequest = store.get(1);
getRequest.onsuccess = function() {
  if (getRequest.result) {
    console.log('找到用户:', getRequest.result);
  } else {
    console.log('未找到');
  }
};

let index = store.index('email');
let findUser = index.get('zhang@example.com');
findUser.onsuccess = () => console.log('通过邮箱找到:', findUser.result);