ExecuteScalar vs ExecuteNonQuery when returning an identity value

Question

Trying to figure out if it\'s best to use ExecuteScalar or ExecuteNonQuery if I want to return the identity column of a newly inserted row. I have

Answer 1

As suggested by Aaron, a stored procedure would make it faster because it saves Sql Server the work of compiling your SQL batch. However, you could still go with either approach: ExecuteScalar or ExecuteNonQuery. IMHO, the performance difference between them is so small, that either method is just as "proper".

Having said that, I don't see the point of using ExecuteScalar if you are grabbing the identity value from an output parameter. In that case, the value returned by ExecuteScalar becomes useless.

An approach that I like because it requires less code, uses ExecuteScalar without output parameters:

public static int SaveTest(Test newTest)
{
    var conn = DbConnect.Connection();
    const string sqlString = "INSERT INTO dbo.Tests ( Tester , Premise ) " +
                             "               VALUES ( @tester , @premise ) " +
                             "SELECT SCOPE_IDENTITY()";
    using (conn)
    {
        using (var cmd = new SqlCommand(sqlString, conn))
        {
            cmd.Parameters.AddWithValue("@tester", newTest.tester);
            cmd.Parameters.AddWithValue("@premise", newTest.premise);

            cmd.CommandType = CommandType.Text;
            conn.Open();
            return (int) (decimal) cmd.ExecuteScalar();

        }
    }
}

Happy programming!

EDIT: Note that we need to cast twice: from object to decimal, and then to int (thanks to techturtle for noting this).