CODEWITHSUNDEEP
javascriptindexeddb
tcak
tcak

Reputation: 2212

IDBDatabase.transaction is always null

I have been following the page Using IndexedDB.

When the page is loaded, I create/load the database.

window.App = window.App || {};
App.db = window.indexedDB.open("myapp", 1);

Following these, I define onerror, onupgradeneeded and onsuccess for App.db object.

In onupgradeneeded, I create a new object store.

Finally, the onsuccess method is called automatically by Javascript because the database is created/loaded. In this method, I list the details of App.db.

App.db.onsuccess = function(ev){
    console.dir( App.db );
};

Console shows that,

readyState = "done" result = IDBDatabase transaction = null

I called the page with file:///, http://localhost, http://myownserver.that.is.forwarded.to.127.0.0.1.from.domain.provider separately.

but the problem persists. The transaction method is null, and I can't do anything, start any transaction. What is the problem, what am I missing?

Upvotes: 0

Views: 317

Answers (1)

Joshua Bell
Joshua Bell

Reputation: 8337

indexedDB.open returns a request object (IDBRequest). So your App.db will hold the request.

It sounds like you have a handle on the upgrade process.

Once that's complete, the connection object (an IDBDatabase instance) is returned via the result property of the request, and you use the transaction() method on the connection object to start transactions. So you'd want to write your "success" handler more like:

App.db.onsuccess = function(ev){
    var connection = App.db.result;
    var tx = connection.transaction(stores, mode);
    ...
};

But it's more common to call the connection object something like db and you don't need to hold on to the request once the connection is opened, so what you probably meant to do is something more like this:

var openRequest = indexedDB.open("myapp", 1);
openRequest.onupgradeneeded = function(e) {
  var db = openRequest.result;
  db.createObjectStore(...);
  ...
};
openRequest.onsuccess = function(e) {
  App.db = openRequest.result;
  var tx = App.db.transaction(...);
};

Upvotes: 2

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