openGauss每日一练第11天

opengauss 数据库管理

1.创建表空间enmtbs和数据库musicdb

--创建表空间
omm=# create tablespace enmtbs relative location 'tablespace/enmtbs11';
CREATE TABLESPACE

--创建数据库
omm=# create database musicdb with tablespace = enmtbs;
CREATE DATABASE
复制

2.查看数据库集簇中有哪些数据库

--元命令查看
omm=# \l
                         List of databases
   Name    | Owner | Encoding | Collate | Ctype | Access privileges 
-----------+-------+----------+---------+-------+-------------------
 musicdb   | omm   | UTF8     | C       | C     | 
 omm       | omm   | UTF8     | C       | C     | 
 postgres  | omm   | UTF8     | C       | C     | 
 template0 | omm   | UTF8     | C       | C     | =c/omm           +
omm=#            |       |          |         |       | omm=CTc/omm
 template1 | omm   | UTF8     | C       | C     | =c/omm           +
           |       |          |         |       | omm=CTc/omm
(5 rows)

--系统表中查询
omm=# select datname from pg_database;
  datname  
-----------
 template1
 omm
 template0
 postgres
 musicdb
(5 rows)

复制

3.查看数据库默认的表空间信息

omm=# select datname,dattablespace ,spcname from pg_database a ,pg_tablespace b where a.dattablespace=b.oid;
  datname  | dattablespace |  spcname   
-----------+---------------+------------
 template1 |          1663 | pg_default
 omm       |          1663 | pg_default
 template0 |          1663 | pg_default
 postgres  |          1663 | pg_default
 musicdb   |         16396 | enmtbs
(5 rows)
复制

4.查看数据库下有哪些模式

--元命令查看
omm=# \dn+
                                         List of schemas
      Name       | Owner | Access privileges |           Description            | WithBlockChain 
-----------------+-------+-------------------+----------------------------------+----------------
 blockchain      | omm   |                   | blockchain schema                | f
 cstore          | omm   |                   | reserved schema for DELTA tables | f
 db4ai           | omm   | omm=UC/omm       +| db4ai schema                     | f
                 |       | =U/omm            |                                  | 
 dbe_perf        | omm   |                   | dbe_perf schema                  | f
 dbe_pldebugger  | omm   | omm=UC/omm       +| dbe_pldebugger schema            | f
                 |       | =U/omm            |                                  | 
 pkg_service     | omm   |                   | pkg_service schema               | f
 public          | omm   | omm=UC/omm       +| standard public schema           | f
                 |       | =U/omm            |                                  | 
 dbe_pldeveloper | omm   | omm=UC/omm       +| dbe_pldeveloper schema           | f
 sqladvisor      | omm   | omm=UC/omm       +| sqladvisor schema                | f
                 |       | =U/omm            |                                  | 
                 |       | =U/omm            |                                  | 
 snapshot        | omm   |                   | snapshot schema                  | f
 uesr1           | uesr1 |                   |                                  | f
(11 rows)

--系统表查询
omm=# select * from information_schema.schemata;
 catalog_name |    schema_name     | schema_owner | default_character_set_catalog | default_character_set_schema | default_character_set_name | s
ql_path 
--------------+--------------------+--------------+-------------------------------+------------------------------+----------------------------+--
--------
 omm          | pg_toast           | omm          |                               |                              |                            | 
 omm          | cstore             | omm          |                               |                              |                            | 
 omm          | pkg_service        | omm          |                               |                              |                            | 
 omm          | dbe_perf           | omm          |                               |                              |                            | 
 omm          | snapshot           | omm          |                               |                              |                            | 
 omm          | blockchain         | omm          |                               |                              |                            | 
 omm          | pg_catalog         | omm          |                               |                              |                            | 
 omm          | public             | omm          |                               |                              |                            | 
 omm          | sqladvisor         | omm          |                               |                              |                            | 
 omm          | information_schema | omm          |                               |                              |                            | 
 omm          | db4ai              | omm          |                               |                              |                            | 
 omm          | uesr1              | uesr1        |                               |                              |                            | 
(14 rows)

 omm          | dbe_pldebugger     | omm          |                               |                              |                            | 
 omm          | dbe_pldeveloper    | omm          |                               |                              |                            | 
复制

5.查询当前连接的数据库下有哪些表：

omm=# select table_catalog, table_schema, table_name, table_type
omm-# from information_schema.tables
         where table_schema not in ('pg_catalog', 'information_schema','dbe_perf')
omm-# ;
 table_catalog |  table_schema   | table_name | table_type 
---------------+-----------------+------------+------------
 omm           | db4ai           | snapshot   | BASE TABLE
 omm           | dbe_pldeveloper | gs_errors  | BASE TABLE
 omm           | dbe_pldeveloper | gs_source  | BASE TABLE
(3 rows)
复制

6.更改数据库默认的表空间

--修改数据库默认表空间
omm=# alter database musicdb set tablespace app_ts;
ALTER DATABASE

--查看数据库默认表空间
omm=# select datname,dattablespace ,spcname from pg_database a ,pg_tablespace b where a.dattablespace=b.oid;
  datname  | dattablespace |  spcname   
-----------+---------------+------------
 template1 |          1663 | pg_default
 omm       |          1663 | pg_default
 template0 |          1663 | pg_default
 postgres  |          1663 | pg_default
 musicdb   |         16391 | app_ts
复制

7.重新命名数据库

omm=# alter database musicdb rename to musicdb1 ;
ALTER DATABASE
omm=# \l
 omm       | omm   | UTF8     | C       | C     | 
 postgres  | omm   | UTF8     | C       | C     | 
 template0 | omm   | UTF8     | C       | C     | =c/omm           +
           |       |          |         |       | omm=CTc/omm
                         List of databases
   Name    | Owner | Encoding | Collate | Ctype | Access privileges 
-----------+-------+----------+---------+-------+-------------------
 musicdb1  | omm   | UTF8     | C       | C     | 
 template1 | omm   | UTF8     | C       | C     | =c/omm           +
           |       |          |         |       | omm=CTc/omm
(5 rows)
复制

8.修改数据库的默认用户

--创建用户user2
omm=# create user user2 identified by 'kunpeng@1234';
NOTICE:  The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE

--修改user2的权限
omm=# alter user user2 sysadmin;
ALTER ROLE

--修改数据库的owner
omm=# alter database musicdb1 owner to user2;
ALTER DATABASE

--查看数据库和owner
omm=# \l
                         List of databases
   Name    | Owner | Encoding | Collate | Ctype | Access privileges 
-----------+-------+----------+---------+-------+-------------------
omm=#  musicdb1  | user2 | UTF8     | C       | C     | 
 omm       | omm   | UTF8     | C       | C     | 
 postgres  | omm   | UTF8     | C       | C     | 
 template0 | omm   | UTF8     | C       | C     | =c/omm           +
           |       |          |         |       | omm=CTc/omm
 template1 | omm   | UTF8     | C       | C     | =c/omm           +
           |       |          |         |       | omm=CTc/omm
(5 rows)

复制

9.删除数据库

omm=# drop database musicdb1;
DROP DATABASE
复制