Check Constraint

[TTT]

I would like to place a check constraint on a column in 1 table against another
column in a separate table.

For example:

if T1.Col1 = 1
then T2.Col1 = 1 or 2

I have done check constraints on single tables but never with 2 or more.

Thanks

[Rune Bivrin]

"TTT" <ttt@ttt.net> wrote in news:3e6c016b$1@tnews.web.devx.com:

>
> I would like to place a check constraint on a column in 1 table
> against another column in a separate table.
>
> For example:
>
> if T1.Col1 = 1
> then T2.Col1 = 1 or 2
>
> I have done check constraints on single tables but never with 2 or
> more.
>
> Thanks
>

The general rule is that constraints can only work with constants and other
columns in the same table. It's possible to work around this in SQL2K by
using a user defined function as the test for the column.

--
Rune Bivrin
- OOP since 1989
- SQL Server since 1990
- VB since 1991

[TTT]

Rune Bivrin <rune@bivrin.com> wrote:
>"TTT" <ttt@ttt.net> wrote in news:3e6c016b$1@tnews.web.devx.com:
>
>>
>> I would like to place a check constraint on a column in 1 table
>> against another column in a separate table.
>>
>> For example:
>>
>> if T1.Col1 = 1
>> then T2.Col1 = 1 or 2
>>
>> I have done check constraints on single tables but never with 2 or
>> more.
>>
>> Thanks
>>
>
>The general rule is that constraints can only work with constants and other

>columns in the same table. It's possible to work around this in SQL2K by

>using a user defined function as the test for the column.
>
>--
>Rune Bivrin
> - OOP since 1989
> - SQL Server since 1990
> - VB since 1991

I accomplished what I wanted to with triggers but did not accomplish my main
goal. I was attempting to show the benefits of xml schemas with the validation
of objects but could not get the cross object constraint to work. Found
another way.
Thanks