Optional Backpointers from Targets to References

This property may be impossible to support for a number of reasons. First its
the same problem that makes maintaining referential integrity difficult and
that has been deferred. Second, there may be significan performance
consequences of trying to maintain the references. And third, creating a
reference to a resource will require modification of the target resource to
update its properties while that resource may not be updatable by the
requesting principal. This is not a good reason for prohibiting a reference. I
recommend that we keep things simple and not add the requirement.




w3c-dist-auth-request@w3.org on 09/15/98 04:02:41 PM
Please respond to w3c-dist-auth-request@w3.org
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Subject: Optional Backpointers from Targets to References

There has been no discussion following Jim Davis's mailnote "Proposal:
optional backpointers for ACR" of August 19.  Unless there are
objections, this proposal will be incorporated in the Advanced
Collections protocol specification, and a corresponding requirement will
be added to the Advanced Collections requirements.

The requirement will state:

There is an interoperable means of navigating from a resource that is
the target of multiple references up the collection hierarchies from
which it is referenced.

The protocol specification will include:

The definition of a new, optional property DAV:references, which
provides backpointers from a target to all resources that refer to it.

This property is live on servers that choose to support it.  It may be
present on resources on other servers, but in that case will be dead.

Clients can use this property to discover which resources reference the
target resource, and by parsing the URLs of the references, can discover
the collections where those references reside and navigate up the
collection hierarchy.

Judith A. Slein
Xerox Corporation
jslein@crt.xerox.com
(716)422-5169
800 Phillips Road 105/50C
Webster, NY 14580

Received on Tuesday, 15 September 1998 17:35:58 UTC