Boolean Variables

If a boolean variable is not initialized it isn’t true or false. Use NVL to have it take the appropriate course.

Declare
 Bool_Var Boolean ;
Begin
 If Not Nvl(Bool_Var,False)
     Then Dbms_Output.Put_Line('False or Not Initialized');
     Else Dbms_Output.Put_Line('True');
 End If;
End;
/

RefCursor Bind Variables

Store select statements in the database and reference them from Sql*Plus. Note: To print again, the PL/Sql block must be executed again.

Variable Emp_Info Refcursor

Begin
   Open :Emp_Info For Select EName
                           , Sal
                        From Emp 
                       Where Job = 'SALESMAN' ;
End;
/

Print Emp_Info