[Zope-dev] ZPatterns Question

[Steve Alexander]

"Phillip J. Eby" wrote:
> 
> Actually, neither relates.  Property sheets created on ZClasses always have
> their data stored in attributes of the object itself, so if you want to
> control those property sheets you would not use a sheet provider at all.

> Sheet providers are only used to provide property sheets whose data is
> stored external to the object.

I'm confused here. Please excuse me if these questions seem silly.


What does "Property sheets created on ZClasses" mean, exactly?


If I use some DataSkin-derived ZClass instances inside a Customizer
folder, and if I want to store the data in the ZODB, do the
propertysheets for one of these ZClass instances come from
PersistentAttributeProviders or PersistentSheetProviders?


What is the difference between a Common Instance Propertysheet and a
Dataskin Attribute Propertysheet when added to a Dataskin-derived
ZClass?


Is the following true, part true, false, or irrelevant?

If I want to add a propertysheet that contains information from an SQL
database query to a ZClass-dataskin instance, I have to :

* Declare in my Product that the ZClass has that propertysheet (unless I
do clever stuff with triggers to add the sheet if it isn't there
already)

* Use a custom SQL SheetProvider? Or an AttributeProvider? Or some
skinscript that calls various methods in my specialist?


Thanks.

--
Steve Alexander
Software Engineer
Cat-Box limited
http://www.cat-box.net