Re: Constraint

mike (hillmw_at_charter.net) wrote:
: Trying to make a constraint

: Instead of a constraint like this:

: ALTER TABLE table_A
: ADD CONSTRAINT XFK_table_A_ID FOREIGN KEY (table_A_ID)
: REFERENCES table_B(table_B_ID)

: I'd like to do something like:

: ALTER TABLE table_A
: ADD CONSTRAINT XFK_table_A_ID FOREIGN KEY (table_A_ID)
: REFERENCES
: table_B, table_C where table_B.id=table_C.id and table_C.level='0'

: Does that make any sence?

Sort of, though I've never tried to do anything like that using a simple constraint definition

_however_

you can certainly write a trigger to enforce this.

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