LINQ to SQL - best way to switch between test & dev db

Question

What is the simplest way to programmatically toggle back and forth between test and dev databases using the LINQ to SQL ORM?

Answer 1

using (MyDataContext dc = new MyDataContext(connectionString) )
{
  //do a unit of work.
}

Answer 2

When newing up a DataContext, one of the overloads takes a connection string. I would therefore have a compiler switch something like:

 #if Debug
 string connectionString = ....
 #else
 string connectionString = ...
 #endif

 DbDataContext db = new DbDataContext(connectionString);

Answer 3

Using a connection string in the web/app config. Have multiple configs for dev/test/prod. Each should have the appropriate connection string. Switch the config for each environment.