Multiple-database Model
The multiple-database model is represented by proposals for shared and private database architect rues, checkout and checking of data to and from shared and private databases．Each user may populates/her private database with data checked out of the shared database, perform updates against the data. and check them back into the shared Database.
The multiple-database model can be used to work around" the conflict situations inherent in long lunation database sessions．Since each user from the shared database and work against. is/her private database, "disconnected" from the、hared database (at least on the surface)，the usersan avoid the conflict situations．In particular, multile users may be simultaneously updating the same thought having to wait for other users to comate late their updates．However, when updated is to benecked into the shared database, it may have to be checked in as a new version, necessitating version management. Further, 'when data in a private data-base references data in the shared data，or vice versa, a private database is not really disconnected from the shared database. For example, the evaluation of query in general will require the database system to access both a private database and the shared data-base, even if the query may have been formulated against a private database．The multiple-database model is more appropriate than the single-database model in an environment where it is easy to determine in advance logical partitions of the database that correspond to work to be performed.
翻译：
多个数据库模式
多个数据库模式是通过共享的和专用的数据库结构来回检查数据的输入结果和输出纤果而体现出来。每一个用户都能给他／她的专用数据库提供从共用数据库那儿检查定义的数据，实行修改数据，检查数招，然后送回共用数据库。
多个数据库模式可用来围绕长期数据库对话所固有的矛盾形势而工作，因为每一个用户可从共用数据库拷贝数据这不同于他／她的专用数据库，该数据库与共用数据库至少在表面上分开，这样用户就能避免矛盾形势。特别是多个用户可能同时修改同一数据，而不必等待其他用户来完成他们的更改。但是，当更改的数据要进入共用数据库检查时，作为新的版本该数据以版本管理为条件可能必须受到检查。进一步说，当专用数据库的数据参考共用数据库的数据时，或反过来说共用数据库的数据参考专用数据库的数据时，一个专用数据库不是真的与共用数据库分沃。例如，评估一般的询问要求数据库系统既存取一个专用数据库也存取一个共用教据库，即使询问可能逆着专用数据库而被明确地阐述。多个数据库模式在一种环境中比单个教据库模式更恰当。在这种环境中容易事先确定与要执行的工作相适应的数据库的分割。