Going from DB2 Enterprise to DB2 Express-C

Downgrading from DB2 Enterprise to DB2 Express-C is a fairly straightforward process.

Stop DB2.

db2stop force

Uninstall DB2 Enterprise.

sudo su - db2inst1
/opt/ibm/db2/V9.7/install/db2_deinstall -a
exit

Install DB2 Express-C without creating any users, etc.

sudo ./db2_install

Update the instance with the new edition information.

sudo /opt/ibm/db2/V9.7/instance/db2iupdt db2inst1

You might encounter this error.

db2inst1@vhost0074:~> db2start
SQL5043N  Support for one or more communications protocols
failed to start successfully. However, core database manager
functionality started successfully.

Look up your DB2 TCP/IP service name. It should be similar to db2c_db2inst1 where db2inst1 is the instance owner.

cat /etc/services | grep db2

Make sure it’s set correctly in the DB2 configuration.

db2 update dbm cfg using SVCENAME db2c_db2inst1

Start DB2.

db2start

You should now have a working DB2 Express-C installation with all the same databases.