在没有往返的情况下更新实体框架6

Question

In EF 4.1, when I wanted to update a record, I could avoid the roundtrip of loading it first by creating a new entity, setting the primary key, attaching it to the DBContext, then updating the field. Change tracking would ensure that only the fields I changed after attaching the entity would update. This method is explained here . But now I'm trying it with EF 6.1 on an ASP.NET project, and find that it doesn't work.

var court_code = new System_Court();
court_code.UID = UID;
SHEntity.System_Court.Attach(court_code);
court_code.Deleted = true;
SHEntity.SaveChanges();

This would have worked previously, but now it gives me a validation error, saying I'm missing various required fields - which I am, but it shouldn't care since Deleted is the only record I want updated. But if I do it with a roundtrip, it works fine.

var court_code = SHEntity.System_Court.Where(w => w.UID == UID).First(); 
court_code.Deleted = true;
SHEntity.SaveChanges();

Is this something that has changed between EF 4 and EF 6? I see that EF 6 generates different looking entity classes than EF 4 did (EF 4 had a bunch of stuff like Entity Key, where as EF 6 looks like a simple POCO). Googling shows a number of changes between EF 4 and 5, but I don't see any mention about how to make this trick work now.

Update: Looking at the sql executed by the second block of code, I see that just Deleted is being updated, as it should.. so is this some issue with creating the object and attaching it like that?

Answer 1

While coding I managed to stumble around the correct answer a few times before finally realizing that I was asking the wrong question. With the help of the comments, I learned about some EF 5 breaking changes involving change tracking, and that helped me realize that it was validation that I needed to disable.

Check out this question for an explanation of it, but essentially what I needed was

SHEntity.Configuration.ValidateOnSaveEnabled = false;