The following examples modify a mapping that calculates the sales for the current month, so it includes only positive values.
This update strategy expression flags records less than 0 for reject and all others for insert:
IIF( SALES > 0, DD_INSERT, DD_REJECT )
This expression uses numeric literals to produce the same result:
IIF( SALES > 0, 0, 3 )
The expression using constants is easier to read than the expression using numeric literals.
The following data-driven example uses DD_REJECT and IS_SPACES to avoid writing spaces to a character column in a target table. This expression flags records that consist entirely of spaces for reject and flags all others for insert: