Procedures are wrapped code containers that usually represent some task.
They don't have to return anything to the main routine.
Functions serve as user-defined operators and return a value to the calling routine.
The only difference between procedures and functions is that functions return some value to the main routine.
SQL> SQL> declare-- www . j a va2 s.c o m 2 v_tx VARCHAR2(50):= 'I just printed my <in> line!';--2 3 procedure p_print 4 (i_string_tx in VARCHAR2, 5 i_replace_tx in VARCHAR2 := 'new') 6 is 7 begin 8 DBMS_OUTPUT.put_line(replace(i_string_tx, 9 '<in>', i_replace_tx)); 10 end; 11 begin 12 p_print (v_tx,'first'); 13 p_print (v_tx,'second'); 14 p_print (v_tx); 15 end; 16 / I just printed my first line! I just printed my second line! I just printed my new line! PL/SQL procedure successfully completed. SQL>
All variables must be declared before declaring any subroutines, such as this procedure.