Ignore duplicate key insert with Entity Framework

Question

I\'m using ASP.NET MVC4 with Entity Framework Code First. I have a table called \"users\", with primary key \"UserId\". This table may have 200,000+ entries.

I need

Answer 1

You can do this:

var newUserIDs = NewUsers.Select(u => u.UserId).Distinct().ToArray();
var usersInDb = dbcontext.Users.Where(u => newUserIDs.Contains(u.UserId))
                               .Select(u => u.UserId).ToArray();
var usersNotInDb = NewUsers.Where(u => !usersInDb.Contains(u.UserId));
foreach(User user in usersNotInDb){
    context.Add(user);
}

dbcontext.SaveChanges();

This will execute a single query in your database to find users which already exist, then filter them out of your NewUsers set.