javascript - 属性/方法无法初始化 indexedDB

Question

无法理解为什么会这样：

var request=window.indexedDB.open("known");    //async IDB request
request.onsuccess=function(){db=event.target.result;
                             alert("database created"+db);  //it works fine database created
                             var store=db.createObjectStore("friends",{pathKey:"name"})  
                             //error **"Uncaught InvalidStateError: An operation was called on an object on which it is not allowed or at a time when it is not allowed."** as on console box                                
                            }

当参考数据库“已知”分配 db 时，为什么会弹出错误？

Answer 1

您只能在版本更改事务中调用 createObjectStore，这大致对应于 upgradeneeded 事件处理程序。此外，它是“keyPath”，而不是“pathKey”。尝试

var request=window.indexedDB.open("known", 2);    //async IDB request
request.onupgradeneeded = function() {
  console.log("got upgradeneeded event");
  db = event.target.result;
  var store = db.createObjectStore("friends", {keyPath: "name"});
}
request.onsuccess=function(){
  console.log("got success event");
  db=event.target.result;                                
}

规范中有一些很好的例子。

Answer 2

看起来你忘了给回调命名参数？尝试：

request.onsuccess = function(event) ...

这样，“事件”就被定义了。