A Mark on a record is an indicator that disappears when the current session ends and which is only visible to the process that is setting the mark. The MARK function sets the mark. The syntax is as follows:

[BooleanValue := ] Record.MARK ( [SetMarkBoolean] )

If the optional BooleanValue and assignment operator (:=) are present, the MARK function will give us the current MARK status (TRUE or FALSE) of the Record. If the optional SetMarkBoolean parameter is present, the Record will be Marked (or unmarked) according to that value (TRUE or FALSE). The default value for SetMarkBoolean is FALSE. The MARK functions should be used carefully, and only when a simpler solution is not readily available. MARKing records can cause significant performance problems on large datasets.