Re: [Zope-dev] bug in zpatterns-0.4 ?
"Phillip J. Eby" wrote: Nope. The two levels of methods (get/retrieve and new/create) are there to seperate Rack-level concerns from implementation concerns. getItem() and newItem() handle maintenance of Rack-level invariants such as the retrieval cache, while retrieveItem() and createItem() deal with object-level invariants. If you called retrieveItem() instead of getItem(), the code would bypass the rack-level invariants managed by getItem(), which would mean in this case that the per-transaction cache would be bypassed. yes, this is a bit more clear to me now. Hm. Seems to me that you should just use two GAP's, one for each DB table, each using "self.id[0]" and "self.id[1]" respectively to determine their primary keys. (cough) why didn't I think about it??? Also, my racks are specialized to have a searchResults method, and a editItem method (until I can find the time to write a decent SQL Attribute setter provider) A reasonable approach. Although, in the case of SQL attribute setting, see my other e-mail from this evening about the use of Generic Triggers to do SQL attribute setting. btw, the genericattributeprovider has saved me a great deal of time. thanks very much! No problem. Did you ever try re-casting your CatalogAwareness replacement to use GenericTrigger instead of a specific Agent plug-in? I did not have the time to do so. I still stick to Zope-2.1.6 for now, and I was afraid of the issues with transaction commit order. and the motto is 'if it ain't break, don't fix it'. I have a contract to upgrade the product in august though. I will look at it at that time. regards, [EMAIL PROTECTED] ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] bug in zpatterns-0.4 ?
At 11:54 AM 6/27/00 +0400, Jephte CLAIN wrote: mike wrote: There is no way to infinite recursion if Rack.getItem is leaved untouched. Ah ah. But people will touch it. Like me for example :-) There is no way to prevent overriding getItem from a ZClass for example. And it *will* recurse infinitely, making Zope dumping core. getItem/newItem are not a high level methods, they are *part of DataSource's protocol* which *implemented* in Rack with retrieveItem and buddies. getItem/newItem are not meant to be overrided. retrieveItem/createItem are to overrided. This is different level for me. When Philipp wake up (I guess he's asleep right now :-)), he might give his opinion about that. I've been on vacation. I'm basically with Mike on this one, with a slight amplification on my intention here. IMHO, what you should be doing with your SQL is making it an AttributeProvider, and using the "virtual" mode of the Rack which does not store the item in the ZODB, only its propertysheets. Then you will not need to override *anything* in any of the ZPatterns classes. If you need to store persistent attributes, this may be an issue. I'm planning to create a "Persistent External Attribute Provider" to allow one to store attributes persistently even when the object itself isn't stored in the ZODB. In any case, my intention for mixed-database objects in racks is that one should not need to override any of the built-in methods of Rack. In earlier versions of ZPatterns, such overriding seemed like it would be necessary, but as of 0.4 there is really no reason at the framework level to mess with any of Rack's implementation details unless you need to create a special hand-tuned version for some critical bit of efficiency. Almost anything you could do by overriding those methods can now be done through Generic Attribute Providers or other plug-ins. ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
[Zope-dev] bug in zpatterns-0.4 ?
hello, Rack.createItem (low level method) first calls Rack.getItem (higher level method) to check the existence of the item. This causes infinite loop in certain cases. It should (IMHO) call Rack.retrieveItem instead regards, jephte clain [EMAIL PROTECTED] ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] bug in zpatterns-0.4 ?
Jephte CLAIN wrote: hello, Rack.createItem (low level method) first calls Rack.getItem (higher level method) to check the existence of the item. This causes infinite loop in certain cases. It should (IMHO) call Rack.retrieveItem instead Could you provide an example please? Mike ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
