Question: every example I seen shows how to do a update query in linq to sql by doing this.

```
// grab entity you want to update

entity.UserId = "123"; // update the fields you want to update.
entity.Name = "bob";

Dbcontext.SubmitChanges();

```

I am wondering can you juse pass in a new object and have it figure it out?

Like could I do this?

```
Enity myEntity = new Entity();
myEntity.UserId = "123";
myEntity.Name = bob:

    // grab entity record
    // shove record ito the found record
    // it figured out what to update and what no to update

```

Answer: 
In the case you have the dbContext available and ready, just add *InsertOnSubmit*:

```
Entity myEntity = new Entity();
myEntity.UserId = "123";
myEntity.Name = bob:

Dbcontext.InsertOnSubmit(myEntity);

Dbcontext.SubmitChanges();

```

As the name of the method implies, this will insert your new entity into the database on calling SubmitChanges.

Marc
If you want to do this for performance reasons then you shouldn't worry about it. Linq to Sql will cache objects locally so that just grabbing an entity by ID to modify some fields is very cheap.