duplicate entries on primary key

Hi!
Using PHP, Pear::DB i managed to put duplicate entries
on a primary key column. My PostgreSQL version is 7.4 self compiled,
running on Slackware 9.1.

Doesn't PK implicate Unique in new version?
--
   Marcin Gil
   marcin.gil @ audax.com.pl, tel. 694972082
   OIS Audax Sp. z o.o., ul. Barlickiego 4, 97-200 Tomaszów Mazowiecki
   tel/fax (44) 7247530, 7244401