In the last episode (Dec 06), Bryan Gintz Work said:
> Is there a way to have unique combinations, so I would have 3
> columns: A, B and C And A, B and C do are not unique, but any
> combination of the three is unique, for example, if I have A=1, B=2,
> C=3 then there can be no other record that each of the columns has
> those exact values. I hope I asked this correctly, Thanks, Bryan
Add a unique key containing all three columns.
CREATE UNIQUE INDEX index1 ON table1 ( a, b, c );