这很简单。

If USER has OBJECTS
then call it SCHEMA
else
     call it USER
end if;

用户可以访问不同用户拥有的模式对象。

基于我对甲骨文的一点了解…USER和SCHEMA有些相似。但也有一个主要的区别。如果“USER”拥有任何对象，则可以将其称为SCHEMA，否则…它将只保留为“USER”。一旦USER拥有至少一个对象，那么根据上面的所有定义....USER现在可以称为SCHEMA。

模式是对象的容器。 它由用户拥有。

从WikiAnswers:

A schema is collection of database objects, including logical structures such as tables, views, sequences, stored procedures, synonyms, indexes, clusters, and database links. A user owns a schema. A user and a schema have the same name. The CREATE USER command creates a user. It also automatically creates a schema for that user. The CREATE SCHEMA command does not create a "schema" as it implies, it just allows you to create multiple tables and views and perform multiple grants in your own schema in a single transaction. For all intents and purposes you can consider a user to be a schema and a schema to be a user.

此外，用户可以访问除自己的模式之外的模式中的对象，如果他们有权限这样做的话。

这个答案没有定义所有者和模式之间的区别，但我认为它增加了讨论的内容。

在我小小的思想世界里:

我一直纠结于这样一个想法:我创建了N个用户，其中每个用户都“消费”(也就是使用)单个模式。

Tim在oracle-base.com上演示了如何做到这一点(有N个用户，每个用户将被“重定向”到单个模式。

他还有第二种“同义词”方法(这里没有列出)。这里我只引用了CURRENT_SCHEMA版本(他的方法之一):

CURRENT_SCHEMA Approach This method uses the CURRENT_SCHEMA session attribute to automatically point application users to the correct schema. First, we create the schema owner and an application user. CONN sys/password AS SYSDBA -- Remove existing users and roles with the same names. DROP USER schema_owner CASCADE; DROP USER app_user CASCADE; DROP ROLE schema_rw_role; DROP ROLE schema_ro_role; -- Schema owner. CREATE USER schema_owner IDENTIFIED BY password DEFAULT TABLESPACE users TEMPORARY TABLESPACE temp QUOTA UNLIMITED ON users; GRANT CONNECT, CREATE TABLE TO schema_owner; -- Application user. CREATE USER app_user IDENTIFIED BY password DEFAULT TABLESPACE users TEMPORARY TABLESPACE temp; GRANT CONNECT TO app_user; Notice that the application user can connect, but does not have any tablespace quotas or privileges to create objects. Next, we create some roles to allow read-write and read-only access. CREATE ROLE schema_rw_role; CREATE ROLE schema_ro_role; We want to give our application user read-write access to the schema objects, so we grant the relevant role. GRANT schema_rw_role TO app_user; We need to make sure the application user has its default schema pointing to the schema owner, so we create an AFTER LOGON trigger to do this for us. CREATE OR REPLACE TRIGGER app_user.after_logon_trg AFTER LOGON ON app_user.SCHEMA BEGIN DBMS_APPLICATION_INFO.set_module(USER, 'Initialized'); EXECUTE IMMEDIATE 'ALTER SESSION SET current_schema=SCHEMA_OWNER'; END; / Now we are ready to create an object in the schema owner. CONN schema_owner/password CREATE TABLE test_tab ( id NUMBER, description VARCHAR2(50), CONSTRAINT test_tab_pk PRIMARY KEY (id) ); GRANT SELECT ON test_tab TO schema_ro_role; GRANT SELECT, INSERT, UPDATE, DELETE ON test_tab TO schema_rw_role; Notice how the privileges are granted to the relevant roles. Without this, the objects would not be visible to the application user. We now have a functioning schema owner and application user. SQL> CONN app_user/password Connected. SQL> DESC test_tab Name Null? Type ----------------------------------------------------- -------- ------------------------------------ ID NOT NULL NUMBER DESCRIPTION VARCHAR2(50) SQL> This method is ideal where the application user is simply an alternative entry point to the main schema, requiring no objects of its own.

这很简单。

If USER has OBJECTS
then call it SCHEMA
else
     call it USER
end if;

用户可以访问不同用户拥有的模式对象。