- From: Jeni Tennison <jeni@jenitennison.com>
- Date: Tue, 22 Jan 2002 09:11:46 +0000
- To: "Arigapudi, Shyam" <Shyam.Arigapudi@ugs.com>
- CC: "'xmlschema-dev@w3.org'" <xmlschema-dev@w3.org>
Hi Shyam, > Have a master type that is abstract. However, it needs to make sure > that some element definitions are present in the derived items (pure > virtual if you will)? If you mean that there are some elements that must be present in instances of all the derived types, then you can include those elements in the base type definition, in the same way as you can include elements in a non-abstract type definition. They will be inherited by the types that derive from them. I'd advise you to arrange those elements in a xs:sequence or xs:choice rather than an xs:all, because if you use an xs:all then the derived types cannot add their own elements to the content model (when deriving by extension). If you allow derivation by restriction, then you should be careful that the common elements aren't optional, because if they are then a derived type could validly leave them out. Cheers, Jeni --- Jeni Tennison http://www.jenitennison.com/
Received on Tuesday, 22 January 2002 04:11:48 UTC