[Zope3-dev] Re: Proposed widget/schema work for the Rivah sprint (Thursday and Friday this week)

[Jim Fulton]

Tres Seaver wrote:
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> Florent Guillaume wrote:
> 
>>Jim Fulton wrote:
>>
>>
>>>I think that sources are different than initial value.  I really don't
>>>see any role that "initial value" has in an object specification.
>>>
>>>A schema is a specification for an object that provides the schema.
>>>An initial value doesn't constrain or specify the object.  If anything,
>>>it constrains applications that create the object, but in a rather
>>>unclear
>>>way.
>>
>>
>>But a schema is useful for more than "specifying the values of an
>>object". All notions of schemas I've encountered (CPS Schemas, XML
>>Schemas, Archetypes) use the schema to constrain or validate an existing
>>object, yes, but also to create new objects from scratch (even in the
>>absence of widgets). Being able to specify initial values is quite
>>important there.
> 
> 
> RDBMS schemas are an important counter to the "default isn't schema"
> case, too.  Defaults become particularly important when migrating
> content "forward" over time.

I wasn't paying attention when I responsed to this the first time. :)
What RDBMS concept are you refering to? NULLs?

Jim

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