Oracle Tips by Burleson

Calling Procedures from PL/SQL

If calling a procedure from SQL*Plus is easy, calling it from PL/SQL is effortless.  Simply call it in the code section of any PL/SQL block . 

SQL> create or replace procedure get_area
  2    (n_length in number,
  3     n_width  in number,
  4     n_area  out number)
  5  as
  6  begin
  7    n_area := n_length*n_width;
  8  end get_area;
  9  / 

Procedure created.

SQL> declare
  2    n_area number :=0;
  3  begin
  4    get_area(10,20,n_area);
  5    dbms_output.put_line('Area '||n_area);
  6  end;
  7  /

Area 200 

Notice that the EXECUTE clause is not used.  That is a SQL*Plus  command and not used in PL/SQL.  Also notice that the n_area variable is not passed by reference as in the SQL*Plus call.  This is because the variable is local where as in the SQL*Plus example, it was external to the database.

The Return Clause with Procedures

As shown in the next section, a PL/SQL function is required to return a value using the RETURN clause.  A procedure can also use the RETURN clause but can not return a value.  Instead, the RETURN clause terminates execution of the procedure and processing passes back to the calling code.  If the procedure was passed OUT or INOUT variables, the procedure will copy their values as of the RETURN clause.  As with the GOTO clause, using the RETURN clause to terminate a procedure is considered bad programming practice and should be avoided. 

The above book excerpt is from:

Easy Oracle PL/SQL Programming

Get Started Fast with Working PL/SQL Code Examples

ISBN 0-9759135-7-3   

John Garmany 

http://www.rampant-books.com/book_2005_1_easy_plsql.htm