I'm a .NET developer and this is the first time i work with oracle provider (Oracle 10g and Framework 4.0). When i add parameter to my command in this way: objCommand.Parameters.Add("pc_cod_id", OracleType.VarChar, 4000).Value = codId; objCommand.Parameters.Add("pc_num_id", OracleType.VarChar, 4000).Value = numId; objCommand.Parameters.Add("return_value", OracleType.Number).Direction = ParameterDirection.ReturnValue; objCommand.Parameters.Add("pc_email", OracleType.VarChar, 4000).Direction = ParameterDirection.Output; I have no problem with the result. But when a add parameter in this way: objCommand.Parameters.Add(CreateParameter(PC_COD_ID, OracleType.VarChar, codId, ParameterDirection.Input)); objCommand.Parameters.Add(CreateParameter(PC_NUM_ID, OracleType.VarChar, numId, ParameterDirection.Input)); objCommand.Parameters.Add(CreateParameter(RETURN_VALUE, OracleType.Number, ParameterDirection.ReturnValue)); objCommand.Parameters.Add(CreateParameter(PC_EMAIL, OracleType.VarChar, ParameterDirection.Output)); The implementation of that function is: protected OracleParameter CreateParameter(string name, OracleType type, ParameterDirection direction) { OracleParameter objParametro = new OracleParameter(name, type); objParametro.Direction = direction; if (type== OracleType.VarChar) { objParametro.Size = 4000; } return objParametro; } All my result are a empty string. My question is, these way to add parameters are not the same? And if no, what is the difference? Thanks :) Add: Sorry i forgot mention "CreateParameter" is a function with multiple implementations the base is the above function, the other use that. protected OracleParameter CreateParameter(string name, OracleType type, object value, ParameterDirection direction) { OracleParameter objParametro = CreateParameter(name, type, value); objParametro.Direction = direction; return objParametro; } The last parameters doesn't need value because those are output parameter, those bring me data from the database.