From: Toby Dickenson On Monday 06 January 2003 3:04 pm, Crosbie Fitch wrote:
But, I'm wondering about a few things: 1) Are all objects in Zope persistent? ZClass instances? Python objects?
No. For example a ZCatalog has one UI 'presence' but is made up of thousands of persistent objects.
Ah, so a ZClass can create instances of 'private' classes that have mixed in the persistence functionality - and these persistent objects won't manifest as entries in Zope folders?
If your stuff looks like a table then use a relational db. If your stuff looks like objects then ZODB will be ok up to several gigabytes.
Well, I can make it look like either very easily. Although, naturally, I don't expect immediate success, I don't want to rue the day I picked a non-scalable choice. If as far as future scalability is concerned, organising my object relationships is better done within a relational database, than directly as persistent objects, then that's what I'll do. The thing is I've heard so much good stuff about Zope, that I don't want to use an external database if the built in system, ZODB is far better suited. As far as I could surmise, external databases may only have been required for incorporation of legacy systems, but I'm beginning to suspect that an external database may be a valid choice for a new system, given scalability requirements. I had wondered if perhaps ZEO was what you added when ZODB ran into its ceiling, but it seems that ZEO is for load balancing rather than scaling capacity.