Oracle中使用者(User)和模式(Schema)的概念，oracleschema

Oracle中使用者(User)和模式(Schema)的概念，oracleschema

資料庫理論中資料庫使用者和資料庫模式並沒有必然的聯絡，詳細的資料庫模式解釋可以在這裡找到：

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.

也就是說資料庫模式可以建立修改，並且可以給不同的使用者訪問也可以賦予不同的使用者。

而Oracle文檔《Concepts》中的解釋是這樣的：

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. 

雖然Oracle中模式也是資料對象的集合，但是在這裡一個使用者對應了一個模式，一個模式只能被一個資料庫使用者所擁有。