On Fri, 2002-08-02 at 09:05, Pierre van Rooden wrote:
> > - Concurrency control (If i'm editing the document at the same time as
> > someone else, the first to save hist content wins and the other one receives
> > a message that the content has been changed since he started editing it)
> This should be the task of MMBase, either the TemporaryNodeManager or 
> the application that uses it. The database can't handle this as you need 
> to maintain a connection to use database locking.
> It can be sued when you sue transactions to put a batch of data in, but 
> otherwis eit is very hard to do on a multi-user system wiotha  limited 
> numbe rof connections.
> Not that the Dove, the xml-communication tool used by the editwizards, 
> does have a certain 'concurrency' checking, but this is AFTER you are 
> done editing (it generates an error if you attempt to commit a node that 
> was changed after you retrieved it for editing).
You are revering here to one instance of MMBase on the database. I think
also that things as concurrency control _could_ be handled by the
database, if the database is too stupid, the database layer should take
care of this. 
For keeping concurrency you dont have to keep your connection, since you
can make a combination of tagging a node for usage by you.
Moving this to an higher level in MMBase would only cause problem's like
not being transparant.

-- 
Eduard Witteveen Systeem Ontwikkelaar
NOS Internet,  Gateway C Kamer 107
+31(0)356772910 http://www.omroep.nl/

Sed quis custodiet ipsos custodes? : The sixth Satire from Juvenal

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