Call now: 252-767-6166  
Oracle Training Oracle Support Development Oracle Apps

 E-mail Us
 Oracle Articles
New Oracle Articles

 Oracle Training
 Oracle Tips

 Oracle Forum
 Class Catalog

 Remote DBA
 Oracle Tuning
 Emergency 911
 RAC Support
 Apps Support
 Oracle Support

 SQL Tuning

 Oracle UNIX
 Oracle Linux
 Remote s
 Remote plans
 Application Server

 Oracle Forms
 Oracle Portal
 App Upgrades
 SQL Server
 Oracle Concepts
 Software Support

 Remote S


 Consulting Staff
 Consulting Prices
 Help Wanted!


 Oracle Posters
 Oracle Books

 Oracle Scripts

Don Burleson Blog 







Oracle Boolean Constraint Tips

Oracle Database Tips by Donald BurlesonJune 10, 2015

Question:  I am trying to create a table that will disallow a NULL value from being inserted into my table, based upon a condition, using an if-then-else. 

I know that I can easily disallow NULL values on insert with the NOT NULL clause, but I want the value to change depending on the value of another inserted column:

  •  If col1 is equal to 1 or 2, then ensure than col2 is null
  • If col2 is equal to 3 or 4 then ensure that col2 is NOT NULL  

In sum, I want to create this complex business rule as a conditional check constraint, using if-then-else logic to check for complex Boolean expressions?

Answer:  You can create complex check constraints that implement conditional logic.  Oracle guru Laurent Schneider shows how to create a table constraint that checks for NULL values based upon the values of other columns in the INSERT statement:

The syntax for using the purge tablespace command is:

create table
    col1 int not null,
    col2 int default null,
    check((col2 is not null and col1 in(3,4)) or (col2 is null and col1 in (1,2)))

You can also create a Boolean datatype with a Boolean check constraint in Oracle table columns:

create table
   tab_bool (
      bool char check (bool in ('N','Y')

As we see, you can make check constraints quite complex and use Boolean logic to enforce complex business rules at the database level.

Also see PL/SQL Boolean data types.

Get the Complete
Oracle SQL Tuning Information 

The landmark book "Advanced Oracle SQL Tuning  The Definitive Reference"  is filled with valuable information on Oracle SQL Tuning. This book includes scripts and tools to hypercharge Oracle 11g performance and you can buy it for 30% off directly from the publisher.




Burleson is the American Team

Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals.  Feel free to ask questions on our Oracle forum.

Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise. All legitimate Oracle experts publish their Oracle qualifications.

Errata?  Oracle technology is changing and we strive to update our BC Oracle support information.  If you find an error or have a suggestion for improving our content, we would appreciate your feedback.  Just  e-mail:  

and include the URL for the page.


Burleson Consulting

The Oracle of Database Support

Oracle Performance Tuning

Remote DBA Services


Copyright © 1996 -  2020

All rights reserved by Burleson

Oracle ® is the registered trademark of Oracle Corporation.



Oracle Training at Sea
oracle dba poster

Follow us on Twitter 
Oracle performance tuning software 
Oracle Linux poster