MySql - apply same unique constraint to two different combinations of fields

Question

How do I specify unique constraint on different combinations of fields? E.g.

 id  | Fld1 | Fld2 | Fld3
-------------------------
  1  |   A  |  B   |  C
-------------------------
  2  |   A  |  C   |  D

I'd like to make the example above illegal because combination (Fld1, Fld3) in row 1 has same values as combination (Fld1, Fld2) in row 2.

Is there any way to do this?

This might be relevant: http://stackoverflow.com/q/229447/2298301 — Dhruv Saxena, Mar 17 '17 at 19:42
Have you checked the link suggested by @DhruvSaxena? Did you understand the approach? With some creativity you can adapt it to your needs. — Giorgos Altanis, Mar 18 '17 at 07:15

score 0 · Answer 1 · answered Mar 17 '17 at 19:45

0

There is no way possible for this except a trigger but performance will be a constraint. You can only have combine unique key but this case will not fullfil.

answered Mar 17 '17 at 19:45

Faizan Younus

793
1
8
13

MySql - apply same unique constraint to two different combinations of fields

1 Answers1