You can change the Clarify schema with either Dovetail's SchemaEditor or Clarify's DDEditor.
Prior to making schema changes, backup the current database.
To make these changes using Dovetail SchemaEditor:
Edit the .SchemaEditor file
Set the database connection information.
Set the inputFilePath to dovetail_admin.schemascript.xml
Preview the changes (SchemaEditor.exe -p).
Apply the changes (SchemaEditor.exe -a).
To make these changes using Clarify DDEditor:
Start the DD Editor program.
To save a copy of the database schema to disk, select Save.
Edit the saved schema file.
Edit the dovetail_admin_schema.sch file. Follow the directions in that file to cut/paste the schema changes into the saved schema file. Use the Apply Changes menu item to compile the new saved schema file.