A change to configuration settings in your web.config leads to an application restart, affecting the Session and Cache objects. How do you prevent it? The answer is by placing configuration information in an external file. To do so, use the little known attribute called ‘configSource’ as shown below:
In the Myconn.config file, declare the connectionStrings as follows:
<add name="nwstring" connectionString="Data Source=(local);Initial
Now you can go ahead and change the connectionString even in a live application without worrying about an application restart!
Make sure you also read about the RestartOnExternalChanges property.