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240 DB2 Deployment Guide
5.5 Updating an existing installation
It is not uncommon that the changes on the database object definitions are
required due the application requirements changed. Frequently, the changes are
taken place at the test system first then deployed to the production system. The
data in the production system sure should be preserved.
To discuss this type of pre-configured database deployment, we define a few
terms used in this section:
Database configuration:
This is the database layout along with the database objects.
Database migration:
Update a database from one configuration to another while preserving its
data. In short, “migration” is also used.
Current configuration:
This is the configuration of the database in the runtime environment (target
environment), thereby, the configuration to be updated.
New configuration:
This is the configuration that the current configuration will be changed to. The
new configuration is derived from the source system.
We use script, that is DDL and SQL statements, as our basic tool. Using the
database backup image is not considered, because the data preservation is a
challenging task.
Two major tasks are necessary for migrating a database. The first is to identify
the changes between the current configuration and the new configuration and
second, apply these changes.
Figure 5-3 illustrates the basic idea of how to migrate the database. Our starting
point is the ITSODB sample database. We make changes on some of the
database objects on the source database ITSODB2 and create a new
configuration. Our task is to migrate ITSODB to have this new configuration.