Using odbc_pconnect function

Hi, Trying to use persistant connections to reduce general access times on my tables, I have the following problem. When creating my connection with: $connectionstring = odbc_pconnect("prov","username","pass"); I'm able to use it on the current page but how do I resuse the variable $connectionstring on other pages since I make calls like: $queryexe = odbc_do($connectionstring, $query); Hope this is not confusing. Also, can I make the persistant connection expire after there have been no calls to the DB for a certain time? Many Thanks, -Luc