tailieunhanh - Hướng dẫn học Microsoft SQL Server 2008 part 82

Khi theo dõi những thay đổi gia tăng, đồng bộ hóa dịch vụ sử dụng theo dõi sự thay đổi mạng cho peer-to-peer đồng bộ hóa. Điều này có nghĩa rằng phiên bản mới nhất là đồng bộ và tất cả các thay đổi cho một hàng đưa ra được áp dụng để ở ngang nhau. Peer-to-peer đồng bộ hóa có thể được so sánh trong nhiều cách để một sự kết hợp của công nghệ dữ liệu thiết lập diễn đàn và nhân rộng | PartV Data Connectivity When tracking incremental changes Sync Services uses net change tracking for peer-to-peer synchronization. This means that the latest version is synchronized and all changes to a given row are applied in order at each peer. Peer-to-peer synchronization can be compared in many ways to a combination of offline data-set technology and replication. Sync Services provides a programming model like that of offline datasets but with a feature set like that of replication. As stated in the previous section replication is a database administrator function but via Sync Services developers can have the same synchronization support through the many available synchronization classes enabling developers to synchronize with other data store types. Like the offline scenario the choice between using peer-to-peer transaction replication versus using Sync Services for peer-to-peer synchronization it comes down to need. Peer-to-peer transactional replication is more of an administrator responsibility but it does provide a highly available and scalable system and requires almost no coding. Sync Services however is for developers. It allows for synchronization of different transports or services and provides synchronization capabilities with data sources other than a database. Sync Services is the mechanism for moving beyond just replicating schema and data from one database to another. From an architecture standpoint the peer-to-peer scenario has each peer containing its own application code and Sync Services code to initiate and facilitate synchronization. This functionality is provided via the Sync Services peer-to-peer API. During a typical synchronization a pair of peers is synchronized. For example given a scenario in which three peers need to be synchronized synchronization could take place like this Peer1 and peer2 are synchronized then peer1 and peer3 and then finally peer2 and peer3. In each synchronization one peer acts as the local peer and one peer .