Hi. I have same problem on some datasets:
Delphi 2010, DOA 4.1.2.0, Oracle 10.2. Some fields in database declared as NVARCHAR2.
The SQL Statement in the TOracleDataSet is:
SELECT g.*, g.ROWID
FROM ware.gp2compl_spec g
WHERE condid = :CONDID
ROWID value is
vsize(g.rowid) = 20
Error...