如何在indexedDB中存储mongodb的集合数组

Question

Hello I want to build a local database for my phonegap so user can use it offline.

I have this in angular function that creates a database.

   function Database() {

    return {
        create: function (itemDocs) {

            var db = null;

            var request = indexedDB.open("myDB", 1);

            request.onsuccess = function (event) {
                db = event.target.result;
                console.log("DB loaded successfully");

            };

            request.onerror = function (event) {
                console.log(event)
            };

            request.onupgradeneeded = function (event) {
                db = event.target.result;
                console.log("DB initiliazed / created");

                //create collections
                db.createObjectStore("items", {keyPath: "_id"});

                //create documents
                var transaction = db.transaction(["items"], "readwrite");

                var items = transaction.objectStore("items");

                items.add(itemDocs);

            };


        }
    }

}

The itemDocs holds a mongoDB collection (which is an array of objects) and I want to store that collection inside indexedDB database the problem im having is that I'm getting this annoying error.

Uncaught InvalidStateError: Failed to execute 'transaction' on 'IDBDatabase': A version change transaction is running.

Answer 1

Use var transaction = event.target.transaction instead of var transaction = db.transaction(...);

A full answer is rather lengthy. Briefly, you don't want to create a new transaction in onupgradeneeded. There is already an active transaction available for you.