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Schema Evolution

From: Naren Chawla <naren@ipedo.com>
Date: Tue, 15 Jan 2002 15:38:50 -0500 (EST)
Message-ID: <EFBAE6044AC0CD41981E01582A1E94AB0463D9@alibaba.ingine.com>
To: <xmlschema-dev@w3.org>
Folks:

XMLSchema's has "evolvability" as one of its goal. Schema Designers can
use several guidelines/best practices to make sure that the schemas can
evolve over period of time. For example,
http://www.xfront.com/ExtendingSchemas.pdf.

Also, schema processor allows some basic changes to the schema without
breaking the current instances. For example, adding a optional
attribute/element, making the occurrence contraints less restrictive,
making several facets on simpleType to be less restrictive, etc..

However, if a user makes structural changes to the schema - for example,
adding a required element to the new schema - this will break the
current instances for that schema.

So, how are people handling this cases ? Are there any open-source tools
which will help directly/indirectly solving this problem of schema
evolution ? Are there any commercially available product s that solve
this problem (Barbadasoft seem to do something in this space,but can't
download their product?).

Thank for your time and attention,

Naren Chawla
Received on Wednesday, 16 January 2002 03:23:31 GMT

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