Thank you.
>In practical sense there is no difference between UNIQUE INDEX and UNIQUE CONSTRAINT. If you want more detailed explanation, google
>
>>
>>I am changing the FK constraint from referencing just one column to two columns (was: CATEGORY, now SITE_NO, CATEGORY).
>>
>>Before the change, I had to DROP UNIQUE FIELD CONSTRAIN on the parent table. Then I created a UNIQUE INDEX (not CONSTRAINT) and then created (on the parent table) the FK_CONSTRANT on the two columns (on the child table). All works.
>>
>>What I don't understand is in which case I would need the UNIQUE FIELD CONSTRAINT (on the parent table)? I had it before, dropped it, created unique index and all works. I am just trying to see if I will miss something by not having the UNIQUE FIELD CONSTRAINT.
>>
>>TIA
"The creative process is nothing but a series of crises." Isaac Bashevis Singer
"My experience is that as soon as people are old enough to know better, they don't know anything at all." Oscar Wilde
"If a nation values anything more than freedom, it will lose its freedom; and the irony of it is that if it is comfort or money that it values more, it will lose that too." W.Somerset Maugham