How to create oracle user for more than one version

Question

I have server under RHEL 6.3 installed on that server Oracle 11gr2 and 12c, I want to create user lets say Ahmad but I want this user to be sysdba on both servers, for single server I edit .bach_profile to be like the following:

11g:

ORACLE_HOSTNAME=oracledev; export ORACLE_HOSTNAME
ORACLE_UNQNAME=DB11G; export ORACLE_UNQNAME
ORACLE_BASE=/oracle11gr2/u01/app/oracle; export ORACLE_BASE
ORACLE_HOME=$ORACLE_BASE/product/11.2.0/db_1; export ORACLE_HOME
ORACLE_SID=DB11G; export ORACLE_SID
PATH=/usr/sbin:$PATH; export PATH
PATH=$ORACLE_HOME/bin:$PATH; export PATH
LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib; export LD_LIBRARY_PATH
CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib; export CLASSPATH
PATH=$PATH:$HOME/bin
unset USERNAME
cd $ORACLE_BASE
export PATH

and if I want to make him sysdba for 12c I use the following:

export TMP=/tmp
export TMPDIR=$TMP
export ORACLE_HOSTNAME=oracledev
export ORACLE_UNQNAME=cdb1
export ORACLE_BASE=/oracle12c/u01/app/oracle
export ORACLE_HOME=$ORACLE_BASE/product/12.1.0/db_1
export ORACLE_SID=cdb1
export PATH=/usr/sbin:$PATH
export PATH=$ORACLE_HOME/bin:$PATH
export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib
export CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib

My question is it possible to marge those parameters together without making a conflict, if yes please advise

Answer 1

For a start you can use oraenv script to set PATH, LD_LIBRARY_PATH, ORACLE_BASE and ORACLE_HOME:

export ORACLE_SID=ORCL
ORAENV_ASK=NO
. /usr/local/bin/oraenv

ORACLE_SID can be parsed from /etc/oratab file. ORACLE_HOSTNAME maybe from HOSTNAME environment variable.

Answer 2

ORACLE_HOME and ORACLE_SID determine where connections go through the IPC protocol. If you can tolerate password authentication, you can use the TCP protocol by specifying a TNSNAMES entry at login. You'll need to add entries for both databases in the TNSNAMES file in each of the two ORACLE_HOMEs.