更新indexeddb中的单个字段

// 打开数据库
var request = indexedDB.open('myDatabase', 1);

request.onerror = function(event) {
  console.log('打开数据库失败');
};

request.onsuccess = function(event) {
  var db = event.target.result;

  // 获取事务
  var transaction = db.transaction(['myStore'], 'readwrite');

  // 获取存储对象
  var store = transaction.objectStore('myStore');

  // 获取数据
  var getRequest = store.get('myKey');

  getRequest.onerror = function(event) {
    console.log('获取数据失败');
  };

  getRequest.onsuccess = function(event) {
    var data = event.target.result;

    // 更新数据
    data.field = 'new value';

    var putRequest = store.put(data, 'myKey');

    putRequest.onerror = function(event) {
      console.log('更新数据失败');
    };

    putRequest.onsuccess = function(event) {
      console.log('更新数据成功');
    };
  };
};

request.onupgradeneeded = function(event) {
  var db = event.target.result;

  // 创建对象存储空间
  var store = db.createObjectStore('myStore', { keyPath: 'key' });
};