[Zope-DB] Per-user connections

[Dieter Maurer]

Yves Bastide writes:
 > For reasons best left in the dark, I'd like to have per-user database 
 > connections.  Since this is in an application where (most of) the SQL is 
 > already done in a module, I see two ways of doing:
 > 
 > * create a Connection object, stored in the Sessin, when the user is 
 > authentified; to use ZSQL methods, subclass the DA to take the 
 > Connection parameter in __call__
This is very difficult, at least with the ZODB based sessions
of the Zope core.

Synchronization is also difficult with pure RAM based sessions,
such as ZSession.

 > * don't count on using ZSQL methods; use a class derived from the one I 
 > use outside of Zope, and from Shared.DC.ZRDB.TM's TM to know when to 
 > commit/rollback.
Why?

 > Can people familiar with Zope's machinery comment on these approaches 
 > (or give me a better one)?
Do not like any of them.

  My favorite approach would be to switch users for each request.

  This requires the database to support user switches for a given
  connection.

  As I read in the SQLRelay documentation, Oracle does support it
  and SQLRelay supports this feature for Oracle.

  With this possibility, you can use the following approach:

          create a DA variant that switches users in its "register"
          method

	  Use an instance of this DA whenever you need
	  user specific database operations.

	  You can use all your Z SQL Methods (once pointed
	  to the required variant for the DA)


Dieter