OraDataReader.GetString
When you call the GetString method on a column containing a null value you get an exception, as stated in the documentation. You also get an exception when you call the GetOraString method. This is a pain, you have to call "IsDBNull(colindex)" before every read of every nullable string column!
Can I suggest you change GetOraString to return an empty (zero length) string for a null string value. If you make coding much simpler.
Regards
Chris