If you want to take care of performance tuning you need to take care of sub-queries as they takes a lot of time to executing in side the pl-sql blocks.

Ref cursor is used to declare a pointer variable. When you return a ref cursor, you are returning a pointer variable.

There are five types of Triggers 1) Data Definition Language triggers: These triggers fire when you make changes to the objects in the database like create, update or delete. They can be implemented...

The function always return a SINGLE value, which includes arrays. Check out the table functions (pipelined), BULK_COLLECT, arrays etc... You can find plenty of examples. "plsql set...