In test and development database environments, it is desirable to use one Oracle installation for multiple databases. The use of a single Oracle installation for multiple databases reduces the amount of space being used and creates a single place for update of binary files. This is easily accommodated in a LINUX or UNIX environment through the proper setting of your .profile or .bash_profile file. In this article we will review the configuration of your profile file to use a single Oracle home with multiple databases.

1. To accomplish the setup of our profile for multiple databases on a single ORACLE_HOME, we will have to create a .profile with three sections: 1. Request for information; 2. Local variables definitions; and 3. global variables definitions. The request for information section will appear to the user upon logon or re-initialization of the .profile and determines which database the user wishes to use. The local variable section defines the variables need to connect to a particular database. The global variable section defines the variables which will be the same regardless of our connection to a certain database.

2. The request for information section defines the variable “database” which is used to set the ORACLE_SID variable, as seen below.

## Beginning of request for information
database=””
while [ -z “$database” ]
do
echo “\n\nEnter database & Oracle version to use:”
echo “1 – ORCL 10.2.0.4 ”
echo “2 – ORCL2 10.2.0.4”
echo “3 – ORCL3 10.2.0.4”
print -n “> ”
read database
if [[ “$database” != “1” &&
“$database” != “2” &&
“$database” != “3” ]]
then
echo “$database” is not valid >&3
database=””
fi
done
## Ending of request for information

3. The local variable section defines all variables for a specific database, as seen below.

##Beginning of local variable definitions
if [[ $database = “1” ]]
then
export ORACLE_SID=orcl
elif [[ $database = “2” ]]
then
export ORACLE_SID=orcl2
elif [[ $database = “3” ]]
then
export ORACLE_SID=orcl3
else
echo “Invalid options ”
fi
## Ending of local variable definitions

4. The global variable section defines all variables for any database using this specific ORACLE_HOME, as seen below.

## Beginning of global variable definitions

## Ending of global variable definitions

5. Place all profile sections into one file named .profile from UNIX or .bash_profile for linux under your /home/{username} directory. In this example, I will place the following text in the file /home/lcatt/.profile for the OS user lcatt.

## Beginning of request for information
database=””
while [ -z “$database” ]
do
echo “\n\nEnter database & Oracle version to use:”
echo “1 – ORCL 10.2.0.4 ”
echo “2 – ORCL2 10.2.0.4”
echo “3 – ORCL3 10.2.0.4”
print -n “> ”
read database
if [[ “$database” != “1” &&
“$database” != “2” &&
“$database” != “3” ]]
then
echo “$database” is not valid >&3
database=””
fi
done
## Ending of request for information

## Ending of global variable definitions

6. Change directory to your home directory with command cd, list current user with command id, and Re-initialize your .profile file as shown below:

$ orcl $ cd
orcl $ id uid=103(lcatt) gid=20(users) groups=200(dba)
orcl $ . ./.profile

7. Upon re-initialization of the profile, you will be able to select the database environment you wish, as seen below. In this example we have select 1 to setup the variables for the database ORCL.

Enter database & Oracle version to use:
1 – ORCL 10.2.0.4
2 – ORCL2 10.2.0.4
3 – ORCL3 10.2.0.4
> 1
Your ORACLE_BASE is set to ‘/opt/app/oracle/product’
Your ORACLE_SID is set to ‘orcl’
Your ORACLE_HOME is set to ‘/opt/app/oracle/product/10.2’
orcl $

This completes setup of .profile for multiple databases using the same oracle home.

Larry J. Catt, OCP 9i, 10g
oracle@allcompute.com
www.allcompute.com