The first one should work as well. It sounds like you have problem with data. There're records in Table3 that do not have corresponding records in Table2.

>Just out of curiosity....
>
>SQL Server won't seem to let me do this:
>
>Table1: Key = ID
>Table2: Key = ID = Table1.ID (Only some Table1 records have a Table2 record)
>Table3: ForeignKey = Table2ID = Table2.ID (Table3's FK must exist in Table2)
>
>I have to do this:
>
>Table1: Key = ID
>Table2: Key = ID = Table1.ID
>Table3: ForeignKey = Table2ID = Table1.ID
>
>I can live with the second method... But the first describes the relationship better and seems safer. Attempting to do it the first way results in:
>
>The ALTER TABLE statement conflicted with the FOREIGN KEY constraint "FK_Table3_Table2ID". The conflict occurred in database "myData", table "dbo.myTable2", column 'ID'.
>
>Is that a known limitation of mixing Foreign keys and Primary keys... or am I missing something?