Hi,
I would like to find an efficient solution for adding/implementing a constraint
UNIQUE on a VARCHAR column not case sensitive:
ALTER TABLE MyTable
ADD CONSTRAINT UNQ_MyTable_MyColumn
UNIQUE (lower(MyColumn)); -- invalid syntax
The idea is to have an index on that column, in a not case sensitive form, i.e.
lower(MyColumn).
SELECT *
FROM MyTable
WHERE lower(MyColumn) = lower('...');
I don't know how to add such a constraint on MyTable except by defining a
trigger on INSERT clause and checking whether lower(:NEW.MyColumn) has been
already inserted in MyTable.
Is there better and more efficient way to do that?
Regards,
--
Daniel
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
