Modify table behavior in a table hierarchy

After you define a table hierarchy, you cannot modify the structure (columns) of the existing tables. However, you can modify the behavior of tables in the hierarchy. Table 1 shows the table behavior that you can modify in a table hierarchy and the syntax that you use to make modifications.
Table 1. Table behavior that you can modify in a table hierarchy
Table behavior Syntax Considerations
Constraint definitions ALTER TABLE To add or drop a constraint, use the ADD CONSTRAINT or DROP CONSTRAINT clause. For more information, see Constraints on tables in a table hierarchy.
Indexes CREATE INDEX, ALTER INDEX For more information, see Add indexes to tables in a table hierarchy and the CREATE INDEX and ALTER INDEX statements in the IBM® Informix® Guide to SQL: Syntax.
Triggers CREATE/DROP TRIGGER You cannot drop an inherited trigger. However, you can drop a trigger from a supertable or add a trigger to a subtable to override an inherited trigger. For information about how to modify triggers on supertables and subtables, see Triggers on tables in a table hierarchy. For information about how to create a trigger, see the IBM Informix Guide to SQL: Tutorial.
All existing subtables automatically inherit new table behavior when you modify a supertable in the hierarchy.
Important: When you use the ALTER TABLE statement to modify a table in a table hierarchy, you can use only the ADD CONSTRAINT, DROP CONSTRAINT, MODIFY NEXT SIZE, and LOCK MODE clauses.