What is the best known practice for insertion...?

[Roiy Zysman]

Hi All,
I'm trying to insert multiple lines to a table with 3 col. All 3 of them
are a part of the primary key.
But while inserting the data , sometime occurs the situation where I
want to insert an already exist entry with the same keys. And mysql
barfs out that this key already exist in the table.
The solution to it would be probably to query for each entry that I'm
about to insert if that entry exists , but it looks like it would be an
enormous overhead. I'm asking this question on a _performance_ context .
What is the best way , ignore the error messages mysql barfs out or
query each entry for existences before inserting it ?

Roiy