database is not updated after submitchanges()

i know this question was asked before but i have this very weird beginner problem:

i want to update a list of actors by an id in which film they played (only one film)

        DataClasses1DataContext db = new DataClasses1DataContext();
        var old = from a in db.Actors
                  where a.id == 1
                  select a;
        db.Log = Console.Out;

        foreach (Actor act in old)
        {
            act.charname = "test";
            act.lastname = "new name";
            act.money = 1324;
        }

        db.S开发者_StackOverflow中文版ubmitChanges();

when i make a select query in my program after i executed this codesnippet the data is changed but when i look in the integrated sql express (server explorer) of my visual studio 2010 nothing happend and when i restart my programm the old vars are there not "test" and "new name" etc..

i dont know what i'm doing wrong i have a dbml file with this table, my table has a primary key and when i debug /breakpoint it on submitchanges() the variables in db changed also

is there something i missed? like a connectionstring or something like that?

thanks for your help!

Are you working with a database you created in SQL Express Server Explorer?

If so: then there is something else wrong.

If not: You're probably looking at the database YOU created. That database gets copied to your output directory (/nameofsolution/nameofproject/bin/debug/nameofdatabase.mdf).

And your SQL gets executed on that database. You're probably looking at the wrong one ;)