Call for Oracle support & training (800) 766-1884
Free Oracle Tips

Home
Corporate Oracle Training
Custom Oracle Training
Oracle New Features Training
Advanced Oracle DBA Classes
Oracle Tuning Courses
Oracle Tips & Tricks
Oracle Training Links
Oracle Training Links
Oracle Training Links

We are top for USA Oracle Training Clients

 

Free Oracle Tips


 
HTML Text AOL

Free Oracle App Server Tips


 
HTML Text

Oracle support

Oracle training

Oracle tuning

Rednecks!

Remote Oracle

Custom Oracle Training

 

   
  Oracle Tips by Burleson

Calling Functions from PL/SQL

In a PL/SQL block, a function can be called in a SQL statement (as seen above) or used in a simple assignment operation.

SQL> declare
  2    v_far  number := &Farenheit;
  3    v_cels number := 0;
  4  begin
  5    v_cels := f2c(v_far);
  6    dbms_output.put_line(
                'Degrees Celcius is '|| f2c(v_far));
  7  end;
  8  / 

Enter value for farenheit: 46 

old   2:   v_far  number := &Farenheit;
new   2:   v_far  number := 46; 

Degrees Celcius is 7.77777777777777777777777777777777777778 

Functions can also be used to validate variables.  In the example below the value of n_test is validated before additional processing.

SQL> create or replace function valid_numb
  2    (n_numb IN number)
  3    return boolean
  4  as
  5  begin
  6    if n_numb < 10 then return true;
  7    else return false;
  8    end if;
  9  end;
 10  / 

Function created.

SQL> declare
  2    n_test number := &Test;
  3  begin
  4    if (valid_numb(n_test))
  5      then dbms_output.put_line('Valid');
  6    else dbms_output.put_line('Invalid');
  7    end if;
  8  end;
  9  / 

Enter value for test: 8 

old   2:   n_test number := &Test;
new   2:   n_test number := 8; 

Valid 

PL/SQL procedure successfully completed. 

SQL> / 

Enter value for test: 12

old   2:   n_test number := &Test;
new   2:   n_test number := 12; 

Invalid 

PL/SQL procedure successfully completed.

This is a simple test to determine if the number is less than 10.  The function valid_numb returns a type Boolean, so it can be used as the condition of a comparison operation.  Line 4 calls the function in order to get a true/false value which is used to control the program execution. 

When should you use a procedure or a function?  Since most modules can be written either as a procedure or a function, the decision between them comes down to efficiency and maintainability.  Functions are preferred when a module returns one value.  This value may be a variable, record or array, but as long as the module always returns one value, it is a good candidate for a procedure. 


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

 
 
 

Oracle performance tuning book

 

 

Oracle performance tuning software

 
Oracle performance tuning software
 
Oracle performance Tuning 10g reference poster
 
Oracle training in Linux commands
 
Oracle training Excel
 
 
 
 

 

email BC:


Copyright © 1996 -  2014 by Burleson Inc. All rights reserved.

Oracle® is the registered trademark of Oracle Corporation.