一个分布式数据库，三个站点分别存放数据 实现水平分片和诱导分片-a distributed database, the three sites were stored data to achieve the level of induction into pieces and patch

OGSA-DAI通过数据服务对后端单个数据源查询，将整串SQL语句推送给后端数据库执行查询。而在面向分布式数据源的DQP查询中，组合查询在中间层被解析为针对不同数据源的子查询，子查询通过DAI数据服务获取查询结果，并在DQP中间层对不同数据源返回的结果进行组装，并返回给请求用户。-OGSA-DAI data services through a single back-end data source query, push the whole string of SQL statements s

Benefit trigger: Its focus is to run and control (system or database administrator) No need to restrictions on the application. The base architecture client / servant, and generally distributed database architecture is very helpful.