>>Hi,
>>
>>I have a method that needs to return either OleDbDataReader or SqlDataReader (depends on the back-end database). Within the method I have IF/ELSE where the code is processed accordingly. But in the method signature I can only specify one type of reader. E.g.
>>

>>public OleDbDataReader MethodName()
>>or
>>public SqlDataReader MethodName()
>>

>>
>>Does it mean that I have to split the method into two methods depending on the type of reader I need to return and deal with it at the calling level?
>
>It depends on whether you need to use any methods or properties that are specific to one or the other. If you don't then you can reference either as IDataReader. eg:

IDataReader dataReader = GetDataReader();
>
>       private IDataReader GetDataReader()
>        {
>            if (YouWantAnSqlReader)
>                return new SqlDataReader();
>            else
>                return new OleDbDataReader();
>        }

I can see that many problems (or good design) can be implemented with using Interfaces. I need to study this topic again.
Thank you.