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?