chopt

Enabling and Disabling Oracle Database Options ( 11.2 ) :

When you install Oracle Database, some options are enabled and others are disabled. If you want to enable or disable a particular database feature for an Oracle home, then shut down the database and use the chopt tool. See Example 5-1.
The chopt tool is a command-line utility that is located in the ORACLE_HOME/bin directory. The syntax for chopt is:

chopt [ enable | disable] db_option

The possible values for db_option are described in the following table:

Value	Description
dm	Oracle Data Mining RDBMS Files
dv	Oracle Database Vault
lbac	Oracle Label Security
olap	Oracle OLAP
partitioning	Oracle Partitioning
rat	Oracle Real Application Testing
ode_net	Oracle Database Extensions for .NET 1.x
ode_net_2	Oracle Database Extensions for .NET 2.0

Example 5-1 Complete Example of Running the Chopt Tool

To enable the Oracle Label Security option in your Oracle binary files, use the following command:

cd %ORACLE_HOME%
srvctl stop database -d myDb
chopt enable lbac
srvctl start database -d myDb 

http://download.oracle.com/docs/cd/E11882_01/install.112/e17162/post_inst_task.htm#CHDFEIJF