Modifying tables

Altering tables
When altering tables, there are some useful options to be aware of, such as the ALTER COLUMN SET DATA TYPE option and the unlimited REORG-recommended operations that can be performed within a single transaction.

Altering materialized query table properties
With some restrictions, you can change a materialized query table to a regular table or a regular table to a materialized query table. You cannot change other table types; only regular and materialized query tables can be changed. For example, you cannot change a replicated materialized query table to a regular table, nor the reverse.

Refreshing the data in a materialized query table
You can refresh the data in one or more materialized query tables by using the REFRESH TABLE statement. The statement can be embedded in an application program, or issued dynamically. To use this statement, you must have DATAACCESS authority, or CONTROL privilege on the table to be refreshed.

Changing column properties
Use the ALTER TABLE statement to change column properties, such as nullability, LOB options, scope, constraints and compression attributes, data types, and so on.