Managing and querying heterogenous and evolving data

近年来，现代信息系统从根本上得到了发展。与传统的数据仓库客户机-服务器体系结构相反，现代信息系统由大量分布式数据源组成，所有这些数据源都通过Internet连接。除了分布式之外，数据源也在不断发展，它们的模式经常异步更新。今天的信息系统也是异构的。除了传统数据库之外，还出现了新的数据源。它们包括实时流数据、数据服务、传感器和射频识别（RFID）读数。

In recent years, modern information systems have evolved in fundamental ways. As opposed to the traditional client-server architecture of data warehouses, modern informations systems consists of large volumes of distributed data sources, all connected by the Internet. Aside from being distributed, the data sources are also evolving, with their schemas updated frequently and asynchronously. Today's information systems are also heterogeneous. Beyond traditional databases, there is an emergence of novel sources of data. They include real-time streamed data, data services, sensor and radio frequency identification (RFID) readings.