trigger interruption on "SPI_execp"

hi,

I table with primary key and in trigger try to insert into this table data
 wich violate constrain (not uniq). When ectually executing SPI_execp I got
 a message "ERROR: cannot insert a duplicate key into a unique index" and
 trigger executing is aborted.
Is there some way to insert uniq data into
table without first cheking using SELECT. Because this table contain >1M
records and SELECT on it is very slow.

best regards,

      Benoît Baudouin

       B2i Toulouse
1 av. de l'Europe 31400 Toulouse
tel 0561003080 fax 0561003085