> To use this to prevent simultaneous inserts of the same data (for
> example if two employees try to insert the same contact into the DB), I
> suppose you could use a constraint (before insert) that checks that
> there is no data matching the md5 checksum, right?
CREATE TABLE blah
(
mymd5 TEXT NOT NULL,
UNIQUE( mymd5 )
);
will do this for you automatically and create an index to enforce it
(don'tcreate another index !)