Database Administrators Stack Exchange is a question and answer site for database professionals who wish to improve their database skills and learn from others in the community. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have seen these 2 extensions used for datafiles, .dat and .dbf while creating and/or altering a tablespace. I'm not sure what the difference between the 2 extensions is, or if .dat is incorrect.

Here are 2 examples from Oracle Database SQL Reference 10g Release 2 (10.2)


   DATAFILE 'tbs_f2.dat' SIZE 40M 


   DATAFILE 'tbs_f03.dbf' SIZE 20M
share|improve this question
Hey, there's also undotbs_1a.f in another example! – Yasir Arsanukaev May 31 '13 at 4:07
@YasirArsanukaev I did notice that one as well. I wasn't sure if it was an error or something since I've seen the .dat' and .dbf` in multiple places. – slybloty May 31 '13 at 4:10
up vote 4 down vote accepted

The extension and the file path don't really matter – the content does. Moreover, when you use Oracle Managed Files (see "Using Oracle Managed Files" in Database Administrator's Guide), Oracle automatically generates file names, you only have to specify the destination path on the file system or on ASM (see "Oracle Automatic Storage Management (Oracle ASM)" in Database Concepts), using initialization parameters such as DB_CREATE_FILE_DEST or DB_RECOVERY_FILE_DEST.

share|improve this answer

The database engine won't care about the extension, it is just a logical name for humans to understand what they are seeing.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.