isMemberByKey

$boolean = $session->isMemberByKey( $object, $table,
      $keytype, $keyvalue] )

The isMemberByKey() function indicates whether an entry in the named object table exists.

 $exists = $session->isMemeberByKey(
   "GA_CompoundDriver::Bridge-Generic-Driver",
   "drivers", [ "INT", 10 ] )