alter table [dbo].[table1] add constraint [FK_table1_building] foreign key ([building],[site_no]) references [dbo].[buildings] ([building],[site_no]) on delete set null on update cascadeBut the above constraint requires that the table Table1 has column SITE_NO (int) as NULL. But I want that the SITE_NO to be NOT NULL. That is, when the entry is deleted from Buildings table I want the column Building in Table1 to be set to NULL but leave the SITE_NO column left without change. Is this possible? Can I modify the ON DELETE part of the above syntax to make it work as I want it? TIA.