Oracle中用户(User)和模式(Schema)的概念

数据库理论中数据库用户和数据库模式并没有必定的联系。具体的数据库模式解释能够在这里找到：

http://stackoverflow.com/questions/2674222/what-is-purpose-of-database-schema

A database schema is a way to logically group objects such as tables, views, stored procedures etc. Think of a schema as a container of objects.You can assign a user login permissions to a single schema so that the user can only access the objects they are authorized to access.

Schemas can be created and altered in a database, and users can be granted access to a schema. A schema can be owned by any user, and schema ownership istransferable.

也就是说数据库模式能够创建改动，而且能够给不同的用户訪问也能够赋予不同的用户。

而Oracle文档《Concepts》中的解释是这种：

A schemais a collection of logical structures of data, or schema objects. A schema is

owned by a database user and has the same name as that user. Each user owns a single
schema. 

尽管Oracle中模式也是数据对象的集合，可是在这里一个用户相应了一个模式，一个模式仅仅能被一个数据库用户所拥有。