Question

I’m having a hard time wrapping my head around when LINQ accesses the database, and how it knows when the optimal time would be. Mainly, this UPDATE statement seems to make two trips to the database. But it shouldn’t — there seems to be no “update” equivalent in LINQ short of querying for a row, updating it, and then saving that change. In basic SQL, I should be able to UPDATE WHERE in one fell swoop.

var query = from u in db.users where u.id == 1 select u;
foreach (user u in query)
{
   u.name = "JOE";
}
db.Save();

I get the magic of Save. It allows me to make multiple changes before committing them. But there still seems to be the initial query for the rows.

Thoughts? Ideas?

EDIT

Now tested, I can confirm that it does in fact go to the database twice. There must be a better way!

Answer 1

If id is the primary key, you can use:

var u = new user { id = 1 };
db.users.Attach(u);
u.name = "JOE";
db.SubmitChanges();