INSERT record IF NOT EXISTS?

[Daevid Vincent]

Does mySQL have a way to INSERT a new record if one doesn't exist (based
upon primary compound key)?

I see this "EXISTS" but not an example of how to use it with INSERT.

I see "INSERT... ON DUPLICATE KEY UPDATE col_name=expr" which is very close,
but I want it to do nothing on duplicate key. :(

mysqladmin  Ver 8.40 Distrib 4.0.24, for pc-linux-gnu on i386

CREATE TABLE `release_test` (                             
  `BID` int(10) unsigned NOT NULL default '0',            
  `ReleaseID` smallint(5) unsigned NOT NULL default '0',  
  `Tested` tinyint(1) unsigned NOT NULL default '0',      
  `CoreID` smallint(3) unsigned NOT NULL default '0', 
  KEY `BID` (`BID`,`ReleaseID`),                          
  KEY `ReleaseID` (`ReleaseID`)                           
) TYPE=MyISAM;