JavaScript如何操作IndexedDB数据库

const request = indexedDB.open('MyDatabase', 1);

request.onupgradeneeded = function(event) {
  const db = event.target.result;
  // 创建一个对象仓库（类似表），主键为 id
  if (!db.objectStoreNames.contains('users')) {
    db.createObjectStore('users', { keyPath: 'id' });
  }
};

request.onsuccess = function(event) {
  const db = event.target.result;
  console.log('数据库打开成功');
};

request.onerror = function(event) {
  console.error('数据库打开失败');
};

function addUser(db, user) {
  const transaction = db.transaction(['users'], 'readwrite');
  const store = transaction.objectStore('users');
  
  const addRequest = store.add(user);

  addRequest.onsuccess = () => {
    console.log('用户添加成功');
  };

  addRequest.onerror = () => {
    console.error('添加失败');
  };
}

function getUser(db, userId) {
  const transaction = db.transaction(['users'], 'readonly');
  const store = transaction.objectStore('users');
  
  const getRequest = store.get(userId);

  getRequest.onsuccess = () => {
    if (getRequest.result) {
      console.log('找到用户:', getRequest.result);
    } else {
      console.log('未找到该用户');
    }
  };
}

function updateUser(db, updatedUser) {
  const transaction = db.transaction(['users'], 'readwrite');
  const store = transaction.objectStore('users');
  store.put(updatedUser);
}

function deleteUser(db, userId) {
  const transaction = db.transaction(['users'], 'readwrite');
  const store = transaction.objectStore('users');
  store.delete(userId);
}