Data Types

Declare
 v_Alpha Varchar2(20)        ;
 v_Today Date                ;
 v_Num   Number(3)           ;
 v_Ctr   Binary_Integer := 1 ; 
 v_T_F   Boolean             ;

You can also have a user-defined type:

 Type t_Rec is Record 
            ( First  Varchar2(20)
            , Last   Varchar2(20)
            );
 v_Name  t_Rec;