Oracle Database Discussions

Hi;

i am already installed oracle 10g(10.2.0.1) on RHEL4U6. I have:

SID:TEST
ORACLE_HOME=/u01/app/oracle/product/10.2.0/db_1
owner=oracle
group=dba

My db is up and running

My question is;

I want to create new user as A and want to use this user instead of oracle user(for testing purpose)

If i follow this:
When db is up
1. chown -R A:dba /u01/app/oracle/product/10.2.0/db_1
2. run /u01/app/oracle/product/10.2.0/db_1/root.sh (edit root.sh change owner from user oracle to A)
3. Add below to user A .bash_profile:

# Oracle Settings
TMP=/tmp; export TMP
TMPDIR=$TMP; export TMPDIR

ORACLE_BASE=/u01/app/oracle; export ORACLE_BASE
ORACLE_HOME=$ORACLE_BASE/product/10.2.0/db_1; export ORACLE_HOME
ORACLE_SID=TEST; export ORACLE_SID
ORACLE_TERM=xterm; export ORACLE_TERM
PATH=/usr/sbin:$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/JRE:$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib; export CLASSPATH
#LD_ASSUME_KERNEL=2.4.1; export LD_ASSUME_KERNEL

4. when i switch user to A i cant stop/start db

What i am missing?

Thanks