Passing Null/empty string to Oracle stored procedure from asp.net

Question

We have an ASP.NET web service that invokes a stored procedure on our DB (Oracle 11g). The problem is that the call to the procedure blows up every time an empty string is pass

Answer 1

You can do the following for any nullable parameters.

oleDBCmd.Parameters.Add(new OracleParameter("to_dt", OracleType.NVarChar));
if(string.IsNullOrEmpty(toDateStr)) {
    oleDBCmd.Parameters["to_dt"].Value = DBNull.Value;
} else {
    oleDBCmd.Parameters["to_dt"].Value = toDateStr;
}
oleDBCmd.Parameters["to_dt"].Direction = ParameterDirection.Input;

That way, you're not relying on string -> null conversion by the oracle adapter.

Edit: If this doesn't fix the issue, it is most possibly a mismatch between types, check NVarChar vs VarChar