What happens if updating cursor did not fetch any records
IN Presence Checking Inequalities When Things Look Bad!
Source definition will look like Similarly create a target definition, go to target designer and create a target flat file with result and error ports. Go to the mapping designer and create a new mapping. TABLE1 - 1000 rows TABLE2 - 1000 rows (A) SELECT t1FROM table1 t1 WHERE t1IN (SELECT t2FROM table2 t2); (B) SELECT t1FROM table1 t1 WHERE EXISTS (SELECT '1' FROM table2 t2 WHERE t2= t1.code) For query A, all rows in TABLE2 will be read for every row in TABLE1. In the case of query B, a maximum of 1 row from TABLE2 will be read for each row of TABLE1, thus reducing the processing overhead of the statement. If the majority of the filtering criteria are in the subquery then the IN vari ation may be more performant. If the majority of the filtering criteria are in the top query then the EXISTS variation may be more performant.
" Alternatives to presence checking include: .