在 oracle 11G 中创建可以访问多个 Schema 的超级用户

Question

我有两个 Schema Schema-1 和 Schema-2。我想创建一个可以同时访问 Schema（Schema-1 和 Schema-2）的超级用户。

我想在 oracle 11g 中使用命令创建一个用户。有可能吗？

Answer 1

这样的用户已经存在；它被称为SYS，拥有数据库。不过，将它用于日常工作并不是一个好主意——您宁愿（如您所愿）创建自己的“超级用户”来做这些事情。例如：

SQL> connect sys as sysdba
Enter password:
Connected.
SQL> create user superuser identified by superman;

User created.

SQL> grant dba to superuser;

Grant succeeded.

好的，我们试试吧：

SQL> connect superuser/superman
Connected.
SQL> select count(*) From scott.emp;

  COUNT(*)
----------
        14

SQL> select table_name from dba_tables where owner = 'MIKE';

TABLE_NAME
------------------------------
EMP
DEPT
BONUS
SALGRADE
DUMMY
ABC

6 rows selected.

SQL> select * from mike.abc;

       KEY         ID        SEQ THINGS     DESCR
---------- ---------- ---------- ---------- ----------
         1          1          0 Food       Chicken
         2          1          1 Cars       BMW
         3          1          2 Sport      Soccer
         4          2          0 Food       Mutton
         5          2          1 Cars       Ford
         6          2          2 Sport      Tennis

6 rows selected.

SQL>

现在，DBA 是该用户的正确角色，我不知道。也许不是，所以也许您宁愿只授予所需的一组权限。是哪一套，我也分不清。

也许授予例如对于schema1 和schema2 用户的表，select 对superuser 的特权。但是，您不能在单个命令中执行此操作 - 您必须为每个用户和他们的每个表分别执行此操作（这意味着 很多 grant select 语句）。让我们试试吧：

SQL> connect sys as sysdba
Enter password:
Connected.
SQL> revoke dba from superuser;

Revoke succeeded.

SQL>

逐句编写是一项无聊的工作，所以我会编写代码来为我编写代码：

SQL> select 'grant select on ' || owner ||'.' ||table_name || ' to superuser;' str
  2  from dba_tables
  3  where owner in ('SCOTT', 'MIKE')
  4  order by owner, table_name;

STR
--------------------------------------------------------------------------------
grant select on MIKE.ABC to superuser;
grant select on MIKE.BONUS to superuser;
grant select on MIKE.DEPT to superuser;
<snip>
grant select on SCOTT.TEST_B to superuser;
grant select on SCOTT.TEST_D to superuser;

26 rows selected.

SQL>

好的；现在复制/粘贴上面的grant 语句并运行它们。

SQL> grant select on MIKE.ABC to superuser;

Grant succeeded.

SQL> grant select on MIKE.BONUS to superuser;

Grant succeeded.

SQL> grant select on MIKE.DEPT to superuser;

Grant succeeded.

<snip>

SQL> grant select on SCOTT.TEST_B to superuser;

Grant succeeded.

SQL> grant select on SCOTT.TEST_D to superuser;

Grant succeeded.

SQL>

有效吗？

SQL> connect superuser/superman
ERROR:
ORA-01045: user SUPERUSER lacks CREATE SESSION privilege; logon denied


Warning: You are no longer connected to ORACLE.
SQL>

啊哈！还不只是！撤销DBA 撤销了大量权限，所以superuser 现在作为用户存在，但不能做任何事情。所以，让我们让它连接到数据库：

SQL> connect sys as sysdba
Enter password:
Connected.
SQL> grant create session to superuser;

Grant succeeded.

SQL> connect superuser/superman
Connected.
SQL> select * From scott.dept;

    DEPTNO DNAME          LOC
---------- -------------- -------------
        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO
        40 OPERATIONS     BOSTON

SQL> select * From mike.abc;

       KEY         ID        SEQ THINGS     DESCR
---------- ---------- ---------- ---------- ----------
         1          1          0 Food       Chicken
         2          1          1 Cars       BMW
         3          1          2 Sport      Soccer
         4          2          0 Food       Mutton
         5          2          1 Cars       Ford
         6          2          2 Sport      Tennis

6 rows selected.

SQL>

对；好多了。这就是我所说的“仅授予所需的一组权限”的意思；不要授予超出某人真正需要的权限。