System for managing local database updates published to different online information services in different formats from a central platform

摘要

The present invention, generally speaking, provides a powerful yet easy to use electronic publishing tool for information providers and online service operators. The electronic publishing tool allows information providers to manage the content they provide to online services. It also reduces the effort required by operations staff of online services to support a growing number of information providers. Finally, the electronic publishing tool allows content to be captured from information providers (and, by extension, subscribers) so that it can be published onto a variety of platforms with minimal additional effort. For example information, in addition to or in lieu of being published on an online service, may be published on CD through a facility such as AppleLink CD (AppleLink CD allows a portion of the "static" content of an online service such as AppleLink to be published and distributed in CD form, with the result that the content is infinitely reusable without incurring connect charges.) Furthermore, information previously published on one online service may be published on one or more other online services, or information may be published on several online services at the same time. A number of potentially "thorny" problems of distributed database systems are solved in an elegant and efficient manner. The first issue involves synchronizing different copies of an item on machines that are not continuously linked at which each copy may be changed independently. Rather than attempting to formulate a set of synchronization policies generally applicable to all items in all instances, synchronization policies are moved from the database engine to the items themselves. The second issue involves lifetime--knowing, given a complex set of interrelationship of items, when an item may be safely deleted. This problem is addressed by providing an interested party mechanism whereby items may "express interest" in each other. When no item is interested in a particular item, that item may safely "go away. "