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Introducing Cloudsync
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Cloudsync CapabilitiesCloudsync provides the usual features that support client/server database applications. It also includes additional capabilities to support distributed applications:
Creating TargetsA publication defines the part of the source database to be shared with a certain set of target databases. A publication can also contain target application code. A single SQL-J command at the source creates a publication that can create and manage any number of targets. A publication restricts the target to only the data the user needs, thus enhancing application performance, security, and transfer time across the network. See Chapter 2, "Publications", for more information on creating and using publications. Synchronizing DatabasesDisconnected databases in a distributed system can change independently. The process that causes each database to reflect changes in the other databases is called synchronization. In Cloudscape synchronization, the refresh operation, invoked by a single SQL-J command at a target, synchronizes data automatically between the target and the source. Changes initiated at any target (or directly at the source) are propagated to other targets as they refresh. When the refresh operation completes, the target is in agreement with the source and therefore has consistent data. See Chapter 4, "Synchronizing Databases", for more details on the refresh operation. Handling ConflictsDifferent databases may attempt to change data in conflicting ways, and the refresh operation must handle this. For example, in an order entry application, the system must avoid corruption if a user at one target orders eight items and a user at another target orders seven items, when only ten items are available. Cloudsync provides a simple framework for handling conflicts:
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![]() Cloudscape Version 3.6 For information about Cloudscape technical support, go to: www.cloudscape.com/support/.Copyright © 1998, 1999, 2000 Informix Software, Inc. All rights reserved. |