The terms Left and Right in MapLeftKey and MapRightKey in the many-to-many mapping with Fluent API can be misunderstood and I guess your problem is caused by this misunderstanding. One might think that it means they describe the columns that are “left” and “right” in the many-to-many join table. That’s actually the case if you … Read more
Everything what you can configure with DataAnnotations is also possible with the Fluent API. The reverse is not true. So, from the viewpoint of configuration options and flexibility the Fluent API is “better”. Configuration examples (for sure not a full list) which are possible in the Fluent API but not with DataAnnotations (as far as … Read more
If I understand correctly, the Status is just a base class and not a base entity participating in Database Inheritance. In such case it’s important to never refer to Status class directly inside entity model and configuration, i.e. no DbSet<Status>, no navigation properties of type Status or ICollection<Status>, no modelBuilder.Entity<Status>() calls and no IEntityTypeConfiguration<Status>. Instead, … Read more
EF Core 5.0 RC1+ As of EF Core 5.0 RC1, it’s possible to do this without an explicit join table. EF Core is able to configure a mapping for the many-to-many relationship shown in your question without requiring you to create a PersonClub type. See What’s New in EF Core 5.0, RC1, Many-to-many in the … Read more
On EF6.2, you can use HasIndex() to add indexes for migration through fluent API. https://github.com/aspnet/EntityFramework6/issues/274 Example modelBuilder .Entity<User>() .HasIndex(u => u.Email) .IsUnique(); On EF6.1 onwards, you can use IndexAnnotation() to add indexes for migration in your fluent API. http://msdn.microsoft.com/en-us/data/jj591617.aspx#PropertyIndex You must add reference to: using System.Data.Entity.Infrastructure.Annotations; Basic Example Here is a simple usage, adding an … 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
var result = from sc in enumerableOfSomeClass join soc in enumerableOfSomeOtherClass on sc.Property1 equals soc.Property2 select new { SomeClass = sc, SomeOtherClass = soc }; Would be equivalent to: var result = enumerableOfSomeClass .Join(enumerableOfSomeOtherClass, sc => sc.Property1, soc => soc.Property2, (sc, soc) => new { SomeClass = sc, SomeOtherClass = soc }); As you can … Read more