Q. How to use Unicode data in my application?
A. Delphi/C++Builder support Unicode strings starting from 2009 version (Tiburon). PostgresDAC supports Unicode data starting from v2.5.0. So, to support Unicode in your application you should use Delphi/C++Builder at least version 2009 and PostgresDAC at least version 2.5.0.
Another issue for Unicode-enabled DB-applications is connection character set. PostgresDAC support Unicode strings only for UTF8 connection characterset. You have to set TPSQLDatabase.CharSet property to 'UTF8' to make PostgresDAC represent strings as Unicode strings.
If TPSQLDatabase.CharSet property value is different from 'UTF8' all strings are treated as single-byte strings with ANSI encoding. Such ANSI-behaviour is the same as for PostgresDAC before 2.5.0 version.