Oracle Database 12c. Please also tag oracle for search purposes.
Oracle is an RDBMS product. Specific releases of the product are known as Oracle9i, Oracle10g, Oracle 11g and Oracle 12c. Generally there are two releases within each major version. Questions tagged oracle12c are assumed to be specific to this version or features introduced in this version.
Questions should probably be additionally tagged oracle for the widest readership.
Questions about SQL in general should probably be tagged sql.
Questions concerning installation or operation may be asked at Server Fault.
Oracle's documentation is quite extensive, and answers to many questions can be found there. It can be found at:
- Oracle 12cR1: http://www.oracle.com/pls/db121/homepage