Database in unity 3d

In my game whenever user opens the game , it should fetch value from a url

void Start () {
	string url = "http:/myurl";
	WWW www = new WWW(url);
            StartCoroutine(WaitForRequest(www)); 
}

IEnumerator WaitForRequest(WWW www)
{
    yield return www;

    // check for errors
    if (www.error == null)
    {
        Debug.Log("WWW Ok!: " + www.data);

    } else {
        Debug.Log("WWW Error: "+ www.error);
    }    
}

I want to save this data in database to use in game.

I am not aware of databse in unity.

Which is the best method for it .

i only know about PlayerPrefab. Any other good method exist?

If user is not connected he should play with already saved data in mobile.
Need good advice and solution ?

Hej there. If you want a small database with not much of a content and without necesarrily internet connectivity I recommend you Sqlite. This is just a file that contains the data but you can access it just like normal SQL.

There are some free Plugins available I used it a while ago and it worked well in Unity

For simple usage you can call a PHP script thats accessing the database. But I think that wouldnt be so secure.