Get the current connectionstring

Get the current connectionstring

  
Hi,

My use-case is as follows.

User logs in with integrated-authentication
UserId is used to swap the connectionstring with a proxy-user and the loggedin user, so the user has its own rights in the databse (and journaling is done by the database)

Now, I only want to change the connectionstring in the session if it's not the right user.
I am toying with the onsessionstart action to do it in that place, but I never trust the start of the session :)
(reuse of sessions etc, especially in tabs etc.)
I can of course use OnBeginWebRequest or a webblock in every page that will change the connection.
but I only want to change it when not correct. so how do I get the session-connectionstring :)