title: Shared SqlConnection
body: <p>Is it good practice to have one shared SqlConnection object in a .NET application to use for all of your database connections or should you have a separate one each time you access the database?</p>
  
  <p>I currently have a shared one and seem to be running into issues all of a sudden. It seems like I can't use a shared one when I need to use SQL authentication mode instead of Windows authentication mode. I just tried for the first time using SQL authentication and it gave me this error when I tried using the same connection a second time:</p>
  
  <p>There is already an open DataReader associated with this Command which must be closed first.</p>