Question

150

Check if IndexedDB database exists

rated 0 times [ 152] [ 2] / answers: 1 / hits: 32236 / 11 Years ago, thu, july 4, 2013, 12:00:00

Is there a way to check if an IndexedDB database already exists? When a program tries to open a database that does not exists the database is created.
The only way that I can think of is something like the following, where I test if an objectStore already exists, if it doesn't, the database is deleted:

var dbexists=false;

var request = window.indexedDB.open(TestDatabase);

request.onupgradeneeded = function(e) {

    db = e.target.result;

    if (!db.objectStoreNames.contains('todo')) {

       db.close();

       indexedDB.deleteDatabase(TestDatabase);

    } else {

       dbexists=true;

    }

}

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answered 11 Years ago deanna · Accepted Answer

In the onupgradeneeded callback you can check the version. (e.target.result.oldversion). If
it is 0, the db didn't exist.

Edit:
After some investigation. You can't be 100% sure if a new db is created. One thing I am sure of is the fact that you can only work with an indexeddb if it has a version 1 or higher. I believe that a db can exist and have a version 0 (The only fact is you can't work with it and the onupgradeneeded event will be called).

I have build my own indexeddbviewer. In that I open the indexeddb without version and if I come in to the onupgradeneeded event, that means the db doesn't exist. In that case I call the abort so it doesn't upgrade to a version 1. This is the way I check it.

var dbExists = true;

var request = window.indexeddb.open("db");

request.onupgradeneeded = function (e){

    e.target.transaction.abort();

    dbExists = false;

}

but as mentioned. It is possible that the db will continue to exist in that case, but the onupgradeneeded will always be called