Business Data Catalog in Microsoft Office SharePoint Server 2007 and the Object Model, Page 4
In the query syntax, note the use of the characters for greater than (">") and lesser than ("<"); they need to be normalized to be understood by the XML schema. After the query construction, the former query is deleted from the properties bag of the method and the new one added in a similar way. All the changes made with the Object Model are persisted in the database by using a SharePoint Timed Job. This means that the replication can take a couple of seconds (in the worse case) before the schema can be used again.
The Business Data Catalog is an important method to bring information from the external world within SharePoint. Users with little or no programming knowledge are able to build BDC schemas in a relatively uncomplicated way, and developers are able to access the extended possibilities of the Object Model to read the information and present it in a desired manner; for example, in custom WebParts. The ability to make alterations is very important because it opens the possibility to interact with an external data source dynamically as well as allowing users to tailor schemas following specific requirements. The Object Model allows schemas to be constructed at run time without a manually-coded XML schema and, includes the possibility to construct adaptive or self-learning schemas that can change based on customer's usage.
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About the Author
Gustavo Velez is a MCSD Senior Application Developer for Winvision (http://www.winvision.nl), a Microsoft Gold Partner in the Netherlands. He has many years experience in developing Windows and Office applications, and more than five years of daily programming experience with SharePoint. The author's articles, in English, Dutch, and Spanish, can be found in many of the leading trade magazines and he's pleased to be Webmaster of http://www.gavd.net/servers, the only Spanish-language dedicated SharePoint site. Spanish-language readers may want to consult the author's new book; "Programación con SharePoint 2007" (http://www.dotnetmania.com/Libros/index.html).