schema和catalog

在数据库中schema和catlog怎么翻译阿，分别代表什么意思。

oracle-schema:
A schema is a collection of database objects (used by a user.).
Schema objects are the logical structures that directly refer to the database’s data.
A user is a name defined in the database that can connect to and access objects.
Schemas and users help database administrators manage database security.

oracle中不可以创建schema，通过创建用户来创建schema.

The database catalog of a database instance consists of metadata in which definitions of database objects such as Basis tables, view tables, synonyms, value ranges, indexes, users, and user groups are stored.

The database catalog is made up of the following sections:

·        Information about the installation of the database system and metadata with the definitions of users and user groups
This part is not assigned to any user or any user group.

·        Metadata for the objects that have been created by a user or a user group
This includes metadata about basis tables and view tables.

schema偶认为是表空间的意思