For Unicode UTF8 databases you will get TWideStringFields. If you previously used a single-byte character database, and if ForceWideStringFields was disabled, you will get TStringFields. To solve this you can:
- Change all fields to TWideStringFields. Now you datasets are Unciode compatible.
- Set Oracle.NoUnicodeSupport to True at run-time in your application before making a connection. Now the database character set will be converted to the client character set of the NLS_LANG variable, which you can force to a single-byte character set.
- Recreate the Oracle19 database with a single-byte character set.