W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > November 2001

datatypes: inheritence in schema RE: datatypes and MT

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Wed, 7 Nov 2001 10:02:52 -0000
To: <w3c-rdfcore-wg@w3.org>
Message-ID: <JAEBJCLMIFLKLOJGMELDOEGMCCAA.jjc@hplb.hpl.hp.com>
> The alternate is to impose the requirement that all lexical
> forms of all data types be valid lexical forms for all
> superordinate types of that data type. Ouch. Tough to
> verify...
> Granted, XML Schema seems to comply with such a requirement
> (I haven't checked rigorously though). But whether we
> could actualy empose such a requirement (either reasonably
> or practically) is questionable.

So, the simple types do appear to follow this.

The  derived types satisfy this by construction.

Derivation by restriction
satisfies this by construction.

Derivation by list
and by union
satisfies this by virtue of not having a superclass (other than

The primitive datatypes inherit from anySimpleType, which appears by
definition to be a union of all the other types, and hence Patrick's
condition is satisfied.

The complex types (which have XML elements - see message later this morning)
seem more difficult, and I think in general Patrick's condition is false. I
am new to XML schema though, having only read part 2 last week, and parts 0
and 1 last night.

Received on Wednesday, 7 November 2001 05:03:11 UTC

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