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

 
 Home
 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
 Analysis
 Design
 Implementation
 Oracle Support


 SQL Tuning
 Security

 Oracle UNIX
 Oracle Linux
 Monitoring
 Remote s
upport
 Remote plans
 Remote
services
 Application Server

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

 Remote S
upport  
 Development  

 Implementation


 Consulting Staff
 Consulting Prices
 Help Wanted!

 


 Oracle Posters
 Oracle Books

 Oracle Scripts
 Ion
 Excel-DB  

Don Burleson Blog 


 

 

 


 

 

 
 

nls_date_format tips

Expert Oracle Database Tips by Donald BurlesonOctober 2, 2015

Oracle nls_date_format tips

Question:  In understand that the internal storage of a DATE or TIMESTAMP column is independent of the display value.  Can you please explain how nls_date_format is used to display date values?

Answer:  The Oracle nls_date_format environmental variable does much more than control the date display within Oracle.  Changing the value of nls_date_format will change the way that the data is displayed in Oracle SQL*Plus:

ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY MM DD';
select sysdate from dual;

ALTER SESSION SET NLS_DATE_FORMAT = 'HH24:MI:SS';
select sysdate from dual;

You can change the way that a date or timestamp column is display at any time by altering your session to re-set nls_date_format.  You can use this alter session set nls_date_format in SQL*Plus, PL/SQL:

alter session set nls_date_format = 'YYYY MM DD';

alter session set nls_date_format = 'HH24:MI:SS';


You can also change the nls_date_format in many procedural languages such as C, C++ COBOL, Java, JavaScript, PHP and many others.  In any language with an Oracle pre-compiler (Pro*C, Pro*COBOL, Pro*Fortran, etc.), you can enter the alter session set nls_date_format directly within your program. 

Oracle will accept the command and comment out the Oracle directives before passing the program to the native language complier.  In other languages that don;t support direct "alter session set nls_date_format", there is separate syntax::

  • Oracle Pro*C: 

    exec sql alter session

  • Perl DBI: 

    $db=DBI->connect("dbi:Oracle:Local","scott","tiger");

    $db->do("ALTER SESSION SET NLS_DATE_FORMAT='DD-MON-RR'");

You can also use the use the to_char format mask to change the display value of a date or timestamp column:

select to_char(sysdate,'HH24:MI:SS') from dual;
select to_char(sysdate,'YYY MM DD') from dual;

The nls_date_format also allows you to display a date up to 1/100 of a second, quite precise date display:

alter session set nls_date_format = 'DD-Mon-YYYY HH24:MI:SS.FF'

Beware, the system wide default for nls_date_format requires a database bounce and you cannot change nls_date_format system wide with an alter system set nls_date_format statement:

SQL> alter system set nls_date_format='Month DD, yyyy';
alter system set nls_date_format='Month DD, yyyy'
*
ERROR at line 1:
ORA-02096: specified initialization parameter is not modifiable with this
option


Also see how to
 change your nls_date_format at login time.

For more details of using nls_date format to change the data display format, see our related notes on using nls_date_format in specific conditions.

 
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 -  2016

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