How To Open A Database In A WebMatrix C# File

In the webMatrix examples, which I have working, it's very easy to access a database. Only three lines are necessary to get up and going:

@{
var db = Database.Open("LOS");
var selectQueryString = "SELECT * FROM wknTest";
}

and a little later,

@foreach(var row in db.Query(selectQueryString)){

There's no using's, no connection strings, all that happens behind the scenes. But now I have enough complicated c# code that I want to separate it into a separate C# file. How would I do the above, but in a C# file residing in the app_code folder in a webMatrix project?