Why we have so many numbers (1,2,3,4) in 11.2.0.3.4 ?. Alright, today I’ll try to explain significance of these numbers and it’s relevance.

11.X .X. X.X
Major Database Release Number:
Major database release number, major new edition, contains significant new functionality. It represents a major new version of the software that contains significant new functionality.

X. 2. X. X
Database Maintenance Release Number:
Number increases when bug fixes or new features to existing programs become available.

X . X .O. X .X
Middleware Release Number:
Release level of Oracle Middleware. In case of 10g/9i it was Oracle Application Server Release Number.

X. X . X. 3. X
Component-Specific/Patch Release Number:
A Patch release contains fixes for serious bugs that cannot wait until the next maintenance releasefor example, component patch sets or interim releases.

X. X . X. X. 4
Platform-Specific Release Number:
Usually this is a patch set Updates.
Used to identify a particular emergency patch release of a software product on that operating system, it usually fixes or works around a particular, critical problem

Views:
SQL> select banner from v$version;
SQL> SELECT * FROM PRODUCT_COMPONENT_VERSION;