Based on this API for stored proc mapping it would be nice to take this use of primary key properties to make the other LeftKey and RightKey API easier to understand:
modelBuilder
.Entity<Tag>()
.HasMany(t => t.Products)
.WithMany(p => p.Tags)
.MapToStoredProcedures(
map =>
{
map.Insert(
f =>
{
f.HasName("ins_product_tag");
f.LeftKeyParameter(t => t.Id, "tag_id");
f.RightKeyParameter(p => p.Id, "product_id");
});
map.Delete(
f =>
{
f.HasName("del_product_tag", "bar");
f.LeftKeyParameter(t => t.Id, "tag_id");
f.RightKeyParameter(p => p.Id, "product_id");
});
});