PL/SQL “Don’ts” 1 & 2
uCatch exceptions with WHEN OTHERS THEN NULL
ØNever catch an
unidentified exception
without logging information
about it.
uForget to handle NULL values
ØAll logical operations (including NOT) that involve NULL values always return FALSE.
ØAll operations (built-in functions, arithmetic) with NULL return NULL, with the following exceptions:
§Concatenations of strings ignore NULL.
§DECODE can compare values with NULL.
ØIn grouping functions (SUM, AVG, COUNT), watch out for NULL values.
§Only not-NULL is processed
