EF7 RC1 : Disable Cascade Delete

问题

In the RC1 of EntityFramework 7, released yesterday, Cascade Delete was added.

To disable it per relationship, I can use :

      builder.Entity<Site>().HasOne(e => e.Person)
      .WithMany(x => x.Sites).Metadata.DeleteBehavior = DeleteBehavior.Restrict;

I want to disable it globally for a DbContext, but I didn't find a way. How can I do ?

回答1:

Someone stated on the github project forum that the only way to do it right now is to iterate through all relationships in the method OnModelCreating(ModelBuilder builder), and set the DeleteBehavior property to DeleteBehavior.Restrict :

        foreach (var relationship in builder.Model.GetEntityTypes().SelectMany(e => e.GetForeignKeys()))
        {
            relationship.DeleteBehavior = DeleteBehavior.Restrict;
        }

回答2:

Right now conventions are not configurable. The current CascadeDelete convention only applies to required relationships. Relationships Conventions: Cascade Delete on efproject.net (Official EF7 docs) You could disable the required relationship explicitly if you understand well the consequences.

        modelBuilder.Entity<Site>()
            .HasOne(p => p.Person)
            .WithMany(b => b.Sites)
            .IsRequired(false);

Otherwise (and recommended), you need to set the On Delete behavior explicitly ( as you already discovered).

        modelBuilder.Entity<Site>()
            .HasOne(p => p.Person)
            .WithMany(b => b.Sites)
            .OnDelete(DeleteBehavior.Restrict);

回答3:

If you don’t use Required on a property in model class, it’s generated as DeleteBehavior.Restrict by default. Use Required if you want to use DeleteBehavior.Cascade. You can see this by generating dummy migrations by using with/without Required.

来源：https://stackoverflow.com/questions/33807879/ef7-rc1-disable-cascade-delete