Entity Framework Core many to many design problem - entity-framework

Question

the idea is that some kind of entity may have many images and images may be linked to many entities. In addition each many-to-many relationship has a number for an ordering position.
So here is what my code looks like:
public abstract class X {
public int Id{get; private set;}
public ICollection<ImageLink> ImageLinks{ get; } = new HashSet<ImageLink>();
...
}
public class A : X {
...
}
public class B : X {
...
}
public class <MANY OTHER CLASSES> : X {
...
}
public class ImageLink {
public int EntityId { get; protected set; }
public int ImageId { get; protected set; }
public virtual X Entity { get; protected set; }
public virtual Image Image { get; protected set; }
public int Position { get; private set; }
....
}
I would like my ef core model to have this kind of inheritance because I don't want to repeat some partial views/controllers code and because it makes sense to me.
I know I can't do this because the image link entity will be mapped in a single table but I need a table for each many-to-many relationship.
Any ideas?

Answer 1

You can configure a different image table per entity if you use owned entities
Now, I couldn't get the navigation property to work from ImageLink to X, but it might be possible to do with generics or something.
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<A>().OwnsMany(a => a.ImageLinks, e =>
{
e.ToTable("ImageLinksForA");
e.WithOwner();
});
modelBuilder.Entity<B>().OwnsMany(a => a.ImageLinks, e =>
{
// Letting EF pick a table name for me
e.WithOwner();
});
// Repeat for each descendent of X
}