how to design a single methon in DAL to retrieve various result from database?

Question

Hi , we have designed our Data Access Layer and parts of it works as a charm without any problem but we have some doubts about designing a method to get a reference of sqlcommand from us and return a single row data from database also the retrieved data has an unknown data type here is what I've done :

//I am using this class as retrieval datatype for now i have only 3 returning data types
public class retDataTypes {

public bool ansBool;
public int ansInt;
public string ansString;

}

public class doQuery {

public retDataTypes returnAnswer(ref sqlcommand cmd , string typeHelper) {

//opening the sqlconnection
//pass the cmd then

retDataTypes  answer = new retDataTypes();

//in most of the cases we need only one row result so that I'm using executeScalar()
switch (typeHelper) {

case "string" :

answer.ansString = cmd.executescalar();
break;

case "int" :
answer.ansInt = cmd.executescalar();
break;

case "bool" :
answer.ansBool = cmd.executescalar();
break;

}

return answer;
}

I need your opinion about this approach is it good ( I know its not efficient) and is there any better ways than this?

please let me know.

regards.

Answer 1

Pass in the SqlCommand without 'ref'.

Change the return type 'retDataTypes' to 'object' and cast it to the type you expect in the calling function.