Обсуждение: Can I habe multi table indices?

Hi,
can I habe multi table indices to ensure that certain IDs can only
appear in on relation?

Like

table_0(id int), table_1(id int), table_2(id int)
rel_1_to_0( id_1 int,  id_0 int )
rel_2_to_0( id_2 int,  id_0 int )

An id of table_0 should only exist either in rel_1_to_0 OR rel_2_to_0.


How can I do this?


regard
Andreas

Andreas wrote:

> can I habe multi table indices to ensure that certain IDs can only
> appear in on relation?
> 
> Like
> 
> table_0(id int), table_1(id int), table_2(id int)
> rel_1_to_0( id_1 int,  id_0 int )
> rel_2_to_0( id_2 int,  id_0 int )
> 
> An id of table_0 should only exist either in rel_1_to_0 OR rel_2_to_0.

You cannot have one index across several tables.

> How can I do this?

Perhaps with a trigger that checks if the condition is satisfied.

Yours,
Laurenz Albe