Using OracleDataReader/OracleDataAdapter in .Net varchar2 column is returning DBNull

See more:

.NET3.0

.NET

C#3.5

Scenario: I have a table with 20 columns of which 2nd column in question is a Varchar2 (255 BYTE) column and I know that the particular query on Oracle SQLDeveloper returns 2 rows both containing proper column values (incidentally column value is 'true' as a string not boolean)

But in .Net environment be it using OracleDataAdapter or OracleDataReader - of the two rows one row consistently is returning object(System.DbNull) for that 2nd column. Not sure why?

Any help is greatly appreciated.