You may have attempted to delete or modify the definition of a column that is part of a primary or foreign key. You may have attempted to delete a column that has an index on it. In this case, DROP the index or key, perform the ALTER statement, and then add the index or key again.

• SQL Anywhere: Primary keys
• SQL Anywhere: Foreign keys
• SQL Anywhere: ALTER TABLE statement
• UltraLite: UltraLite tables and columns
• UltraLite: ALTER TABLE statement [UltraLite]