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EXAM TIPFor the exam, understand that the XmlReader provides the fastest means to access XML data and is read-only, forward-only. 阅读全文
摘要：
The DataContext object manages object identity for you so that rows retrieved from the database table are automatically logged in the DataContext object’s internal identity table by the row’s primary key when the object is created. If the same row is retrieved again by this DataContext object, the o 阅读全文