How to delete child automatically based on parent deletion for database first approach (.edmx)? [duplicate]

Answer 1

EF automatically deletes related records in the middle table for many-to-many relationship entities if one or the other entity is deleted.

Thus, EF enables the cascading delete effect by default for all the entities.

If you want manually handle you can use:

 .WillCascadeOnDelete(false);


 protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<parent>()
            .HasOptional<child>(c => c.child)
            .WithMany()
            .WillCascadeOnDelete(false);
    }

Answer 2

Read about delete behaviour in Entity Framework.

You can choose how an enitity behave on delete so it can affect child/dependant.

In your case you need "Cascade" delete behaviour which automatically delete children/dependants of the entity you are deleting.

Do it like this in you OnModelCreating method:

 protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<PARENT>()
             .........
            .OnDelete(DeleteBehavior.Cascade);
    }

Take a look here on how to use and what is about:

https://entityframeworkcore.com/saving-data-cascade-delete#:~:text=Entity%20Framework%20Core%20Cascade%20Delete&text=Cascade%20delete%20allows%20the%20deletion,delete%20behaviors%20of%20individual%20relationships.