FAQ: Can I build a unique or ascending index on an ArcSDE feature class or table?
Can I build a unique or ascending index on an ArcSDE feature class or table?
ArcCatalog does not allow me to build a unique or ascending attribute index on an ArcSDE feature class or table, but I can do this programmatically.
ArcCatalog's behavior is correct. When creating indexes on ArcSDE feature classes and tables in ArcCatalog, you cannot define these indexes as unique or ascending; this is by design. However, at the geodatabase component level, ITable::AddIndex will not prevent you from creating this kind of index on ArcSDE data. The correct method for creating unique or ascending indexes on ArcSDE data depends on the underlying DBMS. Creating this kind of index programmatically will cause problems with the data if the underlying DBMS does not support it.