课程作业
1.创建一个名为testsm、testsm1的模式
2.创建一个用户john, 并将testsm的owner修改为john，且修改owner前后分别使用\dn+查看模式信息
3.重命名testsm为testsm2
4.在模式testsm1中建表t1、插入记录和查询记录
5.在会话级设置模式搜索顺序
6.在数据库级设置模式搜索顺序
7.在用户级设置模式搜索顺序
1.实验准备
su - omm
gsql -d omm -p 15400 -r
--执行如下的命令和SQL语句，创建表空间enmtbs和数据库enmdb：
CREATE TABLESPACE enmtbs RELATIVE LOCATION 'tablespace/enmtbs1';
CREATE DATABASE enmdb WITH TABLESPACE = enmtbs;
–执行下面的gsql元命令\l，查看openGauss数据库集群上有哪些数据库：
\l
--执行下面的gsql元命令\db，查看openGauss数据库集群上有哪些表空间：
\db
2.查看openGauss数据库上有哪些用户和模式
--执行下面的gsql元命令\du，查看openGauss数据库上有哪些用户：
\du
--执行下面的gsql元命令\dn，查看openGauss数据库上有哪些模式
\dn
3.创建一个数据库用户john，其密码为kunpeng@1234，并授予数据库用户john SYSADMIN权限：
--创建数据库用户user1的同时，会在系统的omm数据库中创建一个与这个用户名同名的模式user1。
CREATE USER john IDENTIFIED BY 'kunpeng@1234';
ALTER USER john SYSADMIN;
--再次执行下面的gsql元命令\du，查看openGauss数据库上有哪些用户：
\du
--再次执行下面的gsql元命令\dn，查看openGauss数据库上有哪些模式
\dn+
--或
SELECT catalog_name, schema_name, schema_owner FROM information_schema.schemata;
--拓展查询
omm=# \dn+ john
List of schemas
Name | Owner | Access privileges | Description | WithBlockChain
------+-------+-------------------+-------------+----------------
john | john | | | f
(1 row)
omm=# SELECT catalog_name, schema_name, schema_owner FROM information_schema.schemata where schema_name='john';
catalog_name | schema_name | schema_owner
--------------+-------------+--------------
omm | john | john
(1 row)
omm=# \du john
List of roles
Role name | Attributes | Member of
-----------+------------+-----------
john | Sysadmin | {}
4.为数据库创建模式
--一个用户可以创建多个模式
--创建一个模式schm1，属主是用户user1，并再次查看当前连接的数据库下有哪些模式：
create schema testsm AUTHORIZATION john;
--继续在数据库enmdb中，创建模式testsm1,属主是用户omm：
create schema testsm1;
\dn
omm=# ALTER SCHEMA testsm rename to testsm2;
ALTER SCHEMA
omm=# \du
List of roles
Role name | Attributes | Member of
-----------+------------------------------------------------------------------------------------------------------------------+-----------
john | Sysadmin | {}
omm | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policyadmin, UseFT | {}
omm=# \dn testsm*
List of schemas
Name | Owner
---------+-------
testsm1 | omm
testsm2 | john
(2 rows)
5.PUBLIC模式、修改模式，模式中建表并插入数据
--openGauss在创建一个新的数据库时，会自动创建一个public模式。当用户登录到该数据库时，如果没有特殊的指定，都是操作在public模式中的数据库对象。
--默认情况下，用户新创建的表，位于public模式中
--执行下面的SQL语句，创建一个测试表test：
create table t1(col1 char(10));
--执行下面的gsql元命令\dt，查看 test表的Schema：
\dt t1
List of relations
Schema | Name | Type | Owner | Storage
--------+------+-------+-------+----------------------------------
public | t1 | table | omm | {orientation=row,compression=no}
(1 row)
omm=# alter table t1 set schema john;
ALTER TABLE
omm=# select * from pg_tables where tablename='t1';
schemaname | tablename | tableowner | tablespace | hasindexes | hasrules | hastriggers | tablecreator | created | last_ddl_time
------------+-----------+------------+------------+------------+----------+-------------+--------------+-------------------------------+-------------------------------
john | t1 | omm | | f | f | f | omm | 2022-12-09 09:30:34.757348+08 | 2022-12-09 09:33:53.941167+08
(1 row)
omm=# \dt t1
No matching relations found.
omm=# alter table john.t1 set schema testsm1;
ALTER TABLE
omm=# \dt
No relations found.
omm=# select * from pg_tables where tablename='t1';
schemaname | tablename | tableowner | tablespace | hasindexes | hasrules | hastriggers | tablecreator | created | last_ddl_time
------------+-----------+------------+------------+------------+----------+-------------+--------------+-------------------------------+-------------------------------
testsm1 | t1 | omm | | f | f | f | omm | 2022-12-09 09:30:34.757348+08 | 2022-12-09 09:42:57.405181+08
(1 row)
omm=# \dt+ t1
No matching relations found.
omm=# \dt+ testsm1.t1
List of relations
Schema | Name | Type | Owner | Size | Storage | Description
---------+------+-------+-------+---------+----------------------------------+-------------
testsm1 | t1 | table | omm | 0 bytes | {orientation=row,compression=no} |
(1 row)
omm=# select * from testsm1.t1;
col1
------
(0 rows)
omm=# insert into testsm1.t1 values ('test');
INSERT 0 1
omm=# insert into testsm1.t1 values ('test1');
INSERT 0 1
omm=# insert into testsm1.t1 values ('test2');
INSERT 0 1
omm=# select * from testsm1.t1;
col1
------------
test
test1
test2
(3 rows)
omm=# create table testsm2.t2(id int);
CREATE TABLE
omm=# insert into testsm2.t2 values (2);
INSERT 0 1
omm=# insert into testsm2.t2 values (3,4,5);
ERROR: INSERT has more expressions than target columns
LINE 1: insert into testsm2.t2 values (3,4,5);
^
omm=# insert into testsm2.t2 values (3),(4);
INSERT 0 2
omm=# select * from testsm2.t2;
id
----
2
3
4
(3 rows)
omm=# \dt+ testsm2.t2
List of relations
Schema | Name | Type | Owner | Size | Storage | Description
---------+------+-------+-------+------------+----------------------------------+-------------
testsm2 | t2 | table | omm | 8192 bytes | {orientation=row,compression=no} |
(1 row)
6.查看和设置模式的搜索路径
--会话级设置模式搜索顺序
#在gsql客户端会话中，执行命令SET SEARCH_PATH TO schm1可以修改模式搜索路径，但只在gsql客户端会话的持续过程中起作用，一旦退出gsql客户端会话，这个设置就丢失了。重新登录gsql会话将模式搜索路径恢复为默认值"$user",public。
omm=# \dt+ testsm2.t2
List of relations
Schema | Name | Type | Owner | Size | Storage | Description
---------+------+-------+-------+------------+----------------------------------+-------------
testsm2 | t2 | table | omm | 8192 bytes | {orientation=row,compression=no} |
(1 row)
omm=#
omm=# show search_path;
search_path
----------------
"$user",public
(1 row)
omm=# \dt+ t2;
No matching relations found.
omm=# set search_path to testsm2;
SET
omm=# show search_path;
search_path
-------------
testsm2
(1 row)
omm=# \dt+ t2;
List of relations
Schema | Name | Type | Owner | Size | Storage | Description
---------+------+-------+-------+------------+----------------------------------+-------------
testsm2 | t2 | table | omm | 8192 bytes | {orientation=row,compression=no} |
(1 row)
omm=#
omm=# \q
[omm@Test-GaussDB-VM 16474]$ gsql -d omm -p 15400 -r
gsql ((openGauss 3.1.0 build 4e931f9a) compiled at 2022-09-29 14:19:24 commit 0 last mr )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.
omm=# show search_path;
search_path
----------------
"$user",public
(1 row)
omm=# \dt+ t2;
No matching relations found.
omm=#
--数据库级设置模式搜索顺序
#修改数据库级别的搜索顺序后，数据库用户user1再次登录到数据库enmdb，其模式搜索路径已经变更为数据库默认的模式搜索路径schm1。
omm=# ALTER DATABASE enmdb SET SEARCH_PATH TO testsm2 ;
ALTER DATABASE
omm=# \c enmdb omm
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "enmdb" as user "omm".
enmdb=# show SEARCH_PATH;
search_path
-------------
testsm2
(1 row)
--用户级设置模式搜索顺序
--设置数据库的用户user1的模式搜索顺序为模式testsm2：
ALTER USER john SET SEARCH_PATH TO testsm2;
omm=> \l+
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges | Size | Tablespace | Description
-----------+-------+-----------+---------+-------+-------------------+-------+------------+--------------------------------------------
enmdb | omm | SQL_ASCII | C | C | | 13 MB | enmtbs |
omm | omm | SQL_ASCII | C | C | =Tc/omm +| 13 MB | pg_default |
| | | | | omm=CTc/omm | | |
postgres | omm | SQL_ASCII | C | C | =Tc/omm +| 28 MB | pg_default | default administrative connection database
| | | | | omm=CTc/omm | | |
template0 | omm | SQL_ASCII | C | C | =c/omm +| 13 MB | pg_default | default template for new databases
| | | | | omm=CTc/omm | | |
template1 | omm | SQL_ASCII | C | C | =c/omm +| 13 MB | pg_default | unmodifiable empty database
| | | | | omm=CTc/omm | | |
(5 rows)
omm=> \dt+
List of relations
Schema | Name | Type | Owner | Size | Storage | Description
---------+------+-------+-------+------------+----------------------------------+-------------
testsm2 | t2 | table | omm | 8192 bytes | {orientation=row,compression=no} |
(1 row)
omm=> \dt+ testsm1.*
List of relations
Schema | Name | Type | Owner | Size | Storage | Description
---------+------+-------+-------+------------+----------------------------------+-------------
testsm1 | t1 | table | omm | 8192 bytes | {orientation=row,compression=no} |
(1 row)
7.搜索顺序的优先级
--会话级模式搜索顺序的优先级最高，用户级模式搜索顺序的优先级第2，数据库级模式搜索顺序的优先级最低。
omm=> alter table testsm1.t1 owner to john;
ALTER TABLE
omm=> select * from pg_tables where tablename like 't_';
schemaname | tablename | tableowner | tablespace | hasindexes | hasrules | hastriggers | tablecreator | created | last_ddl_time
------------+-----------+------------+------------+------------+----------+-------------+--------------+-------------------------------+-------------------------------
testsm1 | t1 | john | | f | f | f | omm | 2022-12-09 09:30:34.757348+08 | 2022-12-09 10:27:12.991426+08
testsm2 | t2 | omm | | f | f | f | omm | 2022-12-09 09:49:14.966124+08 | 2022-12-09 09:49:14.966124+08
(2 rows)
omm=> \dt+ testsm1.*
List of relations
Schema | Name | Type | Owner | Size | Storage | Description
---------+------+-------+-------+------------+----------------------------------+-------------
testsm1 | t1 | table | john | 8192 bytes | {orientation=row,compression=no} |
(1 row)
omm=> \dt+ testsm2.*
List of relations
Schema | Name | Type | Owner | Size | Storage | Description
---------+------+-------+-------+------------+----------------------------------+-------------
testsm2 | t2 | table | omm | 8192 bytes | {orientation=row,compression=no} |
(1 row)
omm=> \dn+ testsm*
List of schemas
Name | Owner | Access privileges | Description | WithBlockChain
---------+-------+-------------------+-------------+----------------
testsm1 | omm | | | f
testsm2 | john | | | f
(2 rows)
--session 会话级模式搜索顺序设置：
set search_path to testsm1;
--user 用户级模式搜索顺序设置（从新连接生效，当前session不生效）：
ALTER USER omm SET SEARCH_PATH TO testsm2;
--database 数据库级模式搜索顺序设置：
ALTER DATABASE enmdb SET SEARCH_PATH TO testsm1;
## 验证过程
[omm@Test-GaussDB-VM 16474]$ gsql -d omm -p 15400 -r
gsql ((openGauss 3.1.0 build 4e931f9a) compiled at 2022-09-29 14:19:24 commit 0 last mr )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.
omm=# \conninfo
You are connected to database "omm" as user "omm" via socket in "/opt/huawei/tmp" at port "15400".
omm=# show search_path;
search_path
----------------
"$user",public
(1 row)
omm=# ALTER DATABASE enmdb SET SEARCH_PATH TO testsm1;
ALTER DATABASE
omm=# show search_path;
search_path
----------------
"$user",public
(1 row)
omm=# \c enmdb omm
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "enmdb" as user "omm".
enmdb=# show search_path;
search_path
-------------
testsm1
(1 row)
enmdb=# ALTER USER omm SET SEARCH_PATH TO testsm2;
ALTER ROLE
enmdb=# show search_path;
search_path
-------------
testsm1
(1 row)
enmdb=# \c omm omm
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "omm" as user "omm".
omm=# show search_path;
search_path
-------------
testsm2
(1 row)
omm=# \c enmdb omm
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "enmdb" as user "omm".
enmdb=# show search_path;
search_path
-------------
testsm2
(1 row)
enmdb=# set search_path to testsm1;
SET
enmdb=# show search_path;
search_path
-------------
testsm1
(1 row)
enmdb=#
8.查看模式有哪些表
--查看当前连接的数据库中，public模式下有哪些表：
select table_catalog,table_schema,table_name,table_type
from information_schema.tables
where table_schema = 'public';
--查看指定数据库中，public模式下有哪些表：
select table_catalog,table_schema,table_name,table_type
from information_schema.tables
where table_catalog='omm' and table_schema = 'public';
最后修改时间：2022-12-09 10:50:34
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