Altering the structure of a table in a table hierarchy

About this task

You cannot use the ALTER TABLE statement to add, drop, or modify the columns of a table in a table hierarchy. You can use the ALTER TABLE statement to add, drop, or modify constraints.

The process of adding, dropping, or modifying a column of a table in a table hierarchy (or otherwise altering the structure of a table) can be a time-intensive task.

To alter the structure of a table in a table hierarchy:

Procedure

  1. Download data from all subtables and the supertable that you want to modify.
  2. Drop the subtables and subtypes.
  3. Modify the unloaded data file.
  4. Modify the supertable.
  5. Recreate the subtypes and subtables.
  6. Upload the data.