IBM Db2 11.1 Certification Guide

Alter table

The alter table statement is used to make modifications to tables, such as adding, dropping, or renaming columns, or changing column attributes. The alter table statement can also be used to:

• Add or drop a column
• Change the append mode
• Change PCTFREE
• Change the compress status
• Change the log index build status
• Set not logged operations

Other changes include adding, attaching, or detaching data partitions, adding or dropping versioning, and adding or dropping security. While the CREATE TABLE statement is the most complex statement in most relational database solutions, the alter statement is not far behind. Take a loot at the  ALTER TABLE statement in the following command:

ALTER TABLE [TableName]ALTER COLUMN [ColumnName] <Modification ...