EntityFramework上下文未保存

Question

I have some actions to my DbContext for save.

I have two Entities - Material and Colors. The entities have relationship many to many.

I try to do this:

var color = context
 .Colors
 .Include("Materials")
 .Where(g => g.Id == (colorId))
 .FirstOrDefault();
var mater = context
 .Materials
 .Include("Colors")
 .SingleOrDefault(c => c.Name == material.Name);
mater.Colors.Add(color);
context.SaveChanges();

When program try to run context.SaveChanges() , it throws an exception DbUpdateException

Unable to update the EntitySet 'MaterialColors' because it has a 
DefiningQuery and no <InsertFunction> element exists in 
the <ModificationFunctionMapping> element to support the current operation.

How to solve it?

Answer 1

Every table mapped by EF must have PK. If it doesn't have PK it will be mapped as readonly view. You must go to your database and in MaterialColors mark both FKs as composite PK. Than update your model.