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.

RDBMS schema are implementation. Zope schemas are *supposed* to be
specification only.

Perhaps it was a bad idea to make schemas interfaces -- I don't
think so. I'd be willing to revisit this. Alternatively, I'd
be happy to see *another* kind of schema that *was* an
implementation, rather than a specification artifact.

Jim

--
Jim Fulton           mailto:[EMAIL PROTECTED]       Python Powered!
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