Improve data access layer select method Pattern

Question

Lately I find myself writing data access layer select methods where the code all takes this general form:

public static DataTable GetSomeData( ... arguments)         


        

Answer 1

Had to add my own:
Return DataReader from DataLayer in Using statement

The new pattern enables me to only have one record in memory at a time, but still encases the connection in a nice 'using' statement:

public IEnumerable GetSomeData(string filter, Func factory)
{
    string sql = "SELECT * FROM [SomeTable] WHERE SomeColumn= @Filter";

    using (SqlConnection cn = new SqlConnection(GetConnectionString()))
    using (SqlCommand cmd = new SqlCommand(sql, cn))
    {
        cmd.Parameters.Add("@Filter", SqlDbType.NVarChar, 255).Value = filter;
        cn.Open();

        using (IDataReader rdr = cmd.ExecuteReader())
        {
            while (rdr.Read())
            {
                yield return factory(rdr);
            }
            rdr.Close();
        }
    }
}