Despite a large number of proposals on version support in the context of computer aided design and software engineering, the absence of a consensus on version semantics has been a key impediment to version support in database systems．Because of the differences between files and databases, it is intuitively clear that the model of versions in database systems cannot be as simple as that adopted in file systems to support software engineering．For data-bases, it may be necessary to manage not only versions of single objects (e.g. a software module, document, but also versions of a collection of objects (e.g. a compound document, a user manual，etc．and perhaps even versions of the schema of database (c.g. a table or a class, a collection of tables or classes)．
   
　　Broadly, there are three directions of research and development in versioning．First is the notion of a parameterized versioning"，that is, designing and implementing a versioning system whose behavior may be tailored by adjusting system parameters This may be the only viable approach, in view of the fact that there are various plausible choices for virtually every single aspect of versioning．The second is to revisit these plausible choices for every aspect of versioning, with the view to discarding some of themes either impractical or flawed. The third is the investigation into the semantics and implementation of versioning collections of objects and of versioning the database schema.

翻译：

数据库的文本管理    

　　在计算机辅助设计和软件工程的环境影响下，尽管对本文支持有许多建议，但对本文语义的意见不一致一直大大妨碍了数据库系统的文本支持。由于文件和数据库之间的差别，从直观上很清楚数据库系统的文本模式不可能与文件系统所采用的支持软件工程的文本模式同样简单。对于数据库来说，有必要不仅管理单个事务的文本（例如，一个软件模块，一份文件等等）而且也要管理许多事务（例如一个复合文件，一个用户手册等等）甚至还要管理数据库构图的文本。（例如一个表格和或一个类别，许多表格，许多类别）。    

　　从广义上说，在文本的研究和发展方面有三个方向。第一，是参数文本的概念，即设计和任一种文本系统，其行为可能通过调节系统参数而改制。鉴于对文本的每一个单方而有许多似乎可行的选择这一事实，这可能是唯一可行的方法。 第二个方向是重访文本每一个方面的可一行的选择，目的在于将其中或者是不实用的或者有毛病的选择丢掉。第三个方向是对语义进行研究并执行描述一大批物体和数据库的构图。