Diplomat: A System for Building and Maintaining Heterogeneous Database Alliances

许多大公司发现自己面临着巨大的遗留数据库问题。他们的数据分布在许多物理上和逻辑上互不相交的语义相关数据库中。到目前为止，对不同类型的数据库系统的互连主要有两种办法：(A)点解决方案，其中支持数据库之间的重点互连的软件系统是在需要和特别的基础上构建的；和(B)全球解决方案，其中创建了一个包含大量数据库的共同的逻辑数据库。(后者的一个变体是联合方法，它涉及一个全局联合管理器，该管理器控制组件数据库之间的所有交互。)Diplomat项目在这两个极端之间选择了一个中间立场，并提供了支持多个松散的数据库互连的技术，称为“联盟”。该框架还提供了在各个数据库之间以及跨联盟执行一致性的机制。该项目借鉴了现有的关于视图规范、数据库间约束和信息流的研究。这项研究证明，大型业务应用程序(如银行、保险和电信)的维护者可以以经济高效、可演进的方式集成多个不同类型的遗留数据库系统。

Many large corporations find themselves with a massive legacy database problem. Their data is distributed across many semantically related databases that are physically and logically disjoint. Until now, there have been two primary approaches for interconnecting heterogeneous database systems: (a) point solutions, in which software systems supporting focused interconnections between databases are constructed on an as-needed and ad hoc basis; and (b) global solutions, in which a common, logical database is created that encompasses a very large number of databases. (A variation of the latter is the federated approach, which involves a global federation manager that controls all interaction between the component databases.) The Diplomat project chooses a middle ground between these two extremes, and provides technology to support multiple loose database interconnections called `alliances`. The framework also provides mechanisms to enforce consistency between individual databases, and across alliances. The project draws on existing research on view specification, inter-database constraints, and information flow. This research serves as a proof of concept that maintainers of large business applications (such as banking, insurance, and telecommunications) can integrate multiple, heterogeneous, legacy database systems in a cost-effective, evolvable fashion.