Operations on Entities › MODIFY Operations

MODIFY Operations

MODIFY (or the synonym ALTER) does the following:

• Changes schema and subschema component entity definitions in the dictionary
• Associates component entities with the current schema or subschema

All clauses valid for ADD operations are also valid for MODIFY operations.

Explicitly Code All Changes

All changes to the existing definition must be explicitly coded. Default values apply to ADD operations only.

Establishes Update Currency

MODIFY SCHEMA and MODIFY SUBSCHEMA statements establish update currency for the specified schema or subschema. Schema or subschema component entities can be updated once update currency is established.

Note: For a discussion of currency, see 9.7, “Establishing Schema and Subschema Currency”.

Use VALIDATE After MODIFY

MODIFY also sets the schema's or subschema's status to IN ERROR. A VALIDATE statement must set the status to VALID before the schema or subschema becomes a usable component.