[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: XLink - Assert linking relationships among more than two resource s
Hien Luu wrote; > >I am looking for a way to maintain referential integrity between two > >different XML files. Eve L. Maler wrote: > Here is an example of a simple link that (by definition) contains the [snip] Perhaps Hien was asking about "referential integrity" in the database context, which means more than asserting a linking relationship. The relationship, and rules about the relationship, are defined to a container (database) that blocks actions that would subvert data integrity. For example, you might have a conference hotel scenario involving parent-child relationships: Conf -> Hotel -> ImageURL ------- ------ ------- Perl Two Marriott www.javaone.com/hotels/marriott.jpg St. Francis www.javaone.com/hotels/stfrancis.jpg AveryE www.javaone.com/hotels/averye.jpg You define a rule to cascade deletions between Hotel and ImageURL. If the AveryE burns down, you delete the parent from the Hotel list and the database engine cascades the deletion to the child (ImageURL == averye.jpg). For the Conference -> Hotel link, you define a different rule. The example data below illustrates why you do not want to cascade deletions from Conference to Hotel if a conference is cancelled. Conf -> Hotel -> ImageURL ------- ------ ------- Java One Marriott www.javaone.com/hotels/marriott.jpg Perl Two Marriott www.javaone.com/hotels/marriott.jpg Given a database scenario, the developer: - defines the relationships - declares the appropriate constraints - relies on the container to maintain referential integrity. I interpreted Hien's inquiry to be "How do I do this if I have two XML files instead of container-enforced referential integrity? Does XLink provide a solution?" ================== Ken North ============================= See you at Java Developer Conference (London, March 13-15, 2000) www.javadevcon.com XML One (Austin, March 29-31, 2000) www.xmlconference.com http://ourworld.compuserve.com/homepages/Ken_North =========================================================== *************************************************************************** This is xml-dev, the mailing list for XML developers. To unsubscribe, mailto:majordomo@x...&BODY=unsubscribe%20xml-dev List archives are available at http://xml.org/archives/xml-dev/ ***************************************************************************
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