Mysql、Oracle中database、schema、use

对于MySQL而言，“database 数据库” 和 “schema 模式” 是同一件事。具体区分如下表：

In MySQL:

• server instance == not identified with catalog, just a set of databases
• database == schema == catalog == a namespace within the server.
• user == named account, who can connect to server and use (but can not own - no concept of ownership) objects in one or more databases
• to identify any object you need (database name + object name)

In Oracle:

• server instance == database == catalog == all data managed by same execution engine
• schema == namespace within database, identical to user account
• user == schema owner == named account, identical to schema, who can connect to database, who owns the schema and use objects possibly in other schemas
• to identify any object you need (schema name + object name)

详细阅读：

1. What's the difference between a catalog and a schema in a relational database?

2. Relationship between catalog, schema, user, and database instance