difference between NextResult and MARS
ado.net, c#, sql-server-mars
Solution
They're almost opposites.
With `.NextResult`, a single piece of code is consuming multiple result sets sequentially. It works through (as much of) each result set in turn by calling `.Read`, and then when it no longer wants to work on that result set, it calls `.NextResult` to move onto the next one. Once you've called `.NextResult`, there's no way to continue consuming the previous result set.
All of these result sets must have been requested as part of the original query that was submitted to generate the `DataReader`. (Either as separate `SELECT` statements, or calling a stored procedure that contains such calls, or a combination of the two)
With MARS, whilst you're consuming a result set through a `DataReader`, you can submit a separate query on the same connection that generates a new, separate `DataReader`. Both readers may be accessed in parallel.
Problem
What's the difference between `using .NextResult` and `Multiple` Active Result Sets? ``` sqlReader.NextResult(); while (sqlReader.Read()) { MessageBox.Show("From third SQL - " + sqlReader.GetValue(0) + " - " + sqlReader.GetValue(1)); } ``` MARS ``` private static string GetConnectionString() { // To avoid storing the connection string in your code, // you can retrive it from a configuration file. return "Data Source=(local);Integrated Security=SSPI;" + "Initial Catalog=AdventureWorks;MultipleActiveResultSets=True"; } ```