After Migrations was introduced in EF 4.3 you can now add indexes when modifying or creating a table. Here is an excerpt from the EF 4.3 Code-Based Migrations Walkthrough from the ADO.NET team blog namespace MigrationsCodeDemo.Migrations { using System.Data.Entity.Migrations; public partial class AddPostClass : DbMigration { public override void Up() { CreateTable( “Posts”, c => … Read more
If you talk about dynamic proxies in EF there are two different types to distinguish: Proxies for lazy loading Proxies for change tracking Usually a change tracking proxy also can serve as a proxy for lazy loading. The reverse is not true. This is because the requirements for change tracking proxies are higher, especially all … Read more
There is a Database Initializer you can use to achieve the migration to latest version on startup (or better, the dbinitializer will kick in on first db access), the MigrateDatabaseToLatestVersion, you use it like that: Database.SetInitializer<ObjectContext>( new MigrateDatabaseToLatestVersion<ObjectContext, Configuration>()); Regarding having one file per migration, if you enable automatic migrations you will find them in … Read more
I found the following post that had an answer for the same problem: The cause of this problem is that in RC and RTM validation no longer lazy loads any properties. The reason this change was made is because when saving a lot of entities at once that have lazy loaded properties validation would get … Read more
If you are using DbContext API (you mentioned ef-code-first) you can simply use: context.YourEntities.Local.Any(e => e.Id == id); or more complex context.ChangeTracker.Entries<YourEntity>().Any(e => e.Entity.Id == id); In case of ObjectContext API you can use: context.ObjectStateManager.GetObjectStateEntries(~EntityState.Detached) .Where(e => !e.IsRelationship) .Select(e => e.Entity) .OfType<YourEntity>() .Any(x => x.Id == id);
Since EF doesn’t handle it automatically, yes, this is the recommend way. I suggest some modifications in article that you provided. Rename your enum public enum FacultyEnum { Eng, Math, Eco } Create a class that represent the table public class Faculty { private Faculty(FacultyEnum @enum) { Id = (int)@enum; Name = @enum.ToString(); Description = … Read more
EF 6 method, using the msdn article: using (var dataContext = new DataModelContainer()) using (var transaction = dataContext.Database.BeginTransaction()) { var user = new User() { ID = id, Name = “John” }; dataContext.Database.ExecuteSqlCommand(“SET IDENTITY_INSERT [dbo].[User] ON”); dataContext.User.Add(user); dataContext.SaveChanges(); dataContext.Database.ExecuteSqlCommand(“SET IDENTITY_INSERT [dbo].[User] OFF”); transaction.Commit(); } Update: To avoid error “Explicit value must be specified for identity … Read more
I got the answer. 🙂 Those cascade deletes were being created because of ManyToManyCascadeDeleteConvention. You need to remove this convention to prevent it from creating cascade deletes for link tables: modelBuilder.Conventions.Remove<ManyToManyCascadeDeleteConvention>();
Collections: It doesn’t matter. There is a distinct difference between collections and references as navigation properties. A reference is an entity. A collections contains entities. This means that initializing a collection is meaningless in terms of business logic: it does not define an association between entities. Setting a reference does. So it’s purely a matter … Read more
EF Code First supports 1:1 and 1:0..1 relationships. The latter is what you are looking for (“one to zero-or-one”). Your attempts at fluent are saying required on both ends in one case and optional on both ends in the other. What you need is optional on one end and required on the other. Here’s an … Read more