课程学习内容
软件版本 ：openGauss 3.0.0
一个用户连接到数据库后，可以在这个数据库中创建多个模式。要访问这些模式，可以使用DatabaseName.SchemaName.TableName或者SchemaName.TableName，来访问某个模式下的一个表。
默认情况下访问public模式下的表，可以不用添加模式名前缀。
数据库实操内容
环境准备
连接数据库 #第一次进入等待15秒 #数据库启动中…
su - omm
gsql -r
root@modb:~# su - omm
omm@modb:~$ gsql -r
gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.
omm=#
创建模式、查看模式
–进入数据库omm，创建表空间、测试数据库
drop DATABASE IF EXISTS musicdb;
drop DATABASE IF EXISTS musicdb1;
drop DATABASE IF EXISTS musicdb2;
drop DATABASE IF EXISTS musicdb3;
drop tablespace IF EXISTS music_tbs;
CREATE TABLESPACE music_tbs RELATIVE LOCATION ‘tablespace/test_ts1’;
CREATE DATABASE musicdb WITH TABLESPACE = music_tbs;
omm=# drop DATABASE IF EXISTS musicdb;
NOTICE: database "musicdb" does not exist, skipping
DROP DATABASE
omm=# drop DATABASE IF EXISTS musicdb1;
NOTICE: database "musicdb1" does not exist, skipping
DROP DATABASE
omm=# drop DATABASE IF EXISTS musicdb2;
NOTICE: database "musicdb2" does not exist, skipping
DROP DATABASE
omm=# drop DATABASE IF EXISTS musicdb3;
DROP DATABASE
omm=# NOTICE: database "musicdb3" does not exist, skipping
omm=# drop tablespace IF EXISTS music_tbs;
NOTICE: Tablespace "music_tbs" does not exist, skipping.
DROP TABLESPACE
omm=# CREATE TABLESPACE music_tbs RELATIVE LOCATION 'tablespace/test_ts1';
CREATE TABLESPACE
omm=# CREATE DATABASE musicdb WITH TABLESPACE = music_tbs;
CREATE DATABASE
omm=#
–执行下面的SQL语句，创建用户user1：
CREATE USER user1 IDENTIFIED BY ‘kunpeng@1234’;
omm=# CREATE USER user1 IDENTIFIED BY 'kunpeng@1234';
NOTICE: The encrypted password contains MD5 ciphertext, which is not secure.
CREATE ROLE
–授予user1数据库系统的SYSADMIN权限：
ALTER USER user1 SYSADMIN;
omm=# ALTER USER user1 SYSADMIN;
ALTER ROLE
omm=#
–使用用户user1连接到数据库musicdb，首先查看当前数据库下有哪些模式；
\q
gsql -d musicdb -U user1 -p 5432 -W kunpeng@1234 -r
\dn
omm=# \q
omm@modb:~$ gsql -d musicdb -U user1 -p 5432 -W kunpeng@1234 -r
gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.
musicdb=> \dn
List of schemas
Name | Owner
-----------------+-------
blockchain | omm
cstore | omm
db4ai | omm
dbe_perf | omm
dbe_pldebugger | omm
dbe_pldeveloper | omm
pkg_service | omm
public | omm
snapshot | omm
sqladvisor | omm
(10 rows)
musicdb=>
然后为数据库musicdb创建4个模式： schm1、 schm2、 schm3、 schm4
–用户user1在数据库musicdb中，创建了4个模式：
create schema schm1 AUTHORIZATION user1;
create schema schm2 AUTHORIZATION user1;
create schema schm3 AUTHORIZATION user1;
create schema schm4 AUTHORIZATION user1;
musicdb=> create schema schm1 AUTHORIZATION user1; CREATE SCHEMA musicdb=> create schema schm2 AUTHORIZATION user1; CREATE SCHEMA musicdb=> create schema schm3 AUTHORIZATION user1; CREATE SCHEMA musicdb=> create schema schm4 AUTHORIZATION user1; CREATE SCHEMA musicdb=>
–查看musicdb数据库下有哪些模式：
\dn
musicdb=> \dn List of schemas Name | Owner -----------------+------- blockchain | omm cstore | omm db4ai | omm dbe_perf | omm dbe_pldebugger | omm dbe_pldeveloper | omm pkg_service | omm public | omm schm1 | user1 schm2 | user1 schm3 | user1 schm4 | user1 snapshot | omm sqladvisor | omm (14 rows) musicdb=>
–除了可以用gsql的元命令\dn来查看数据库有哪些模式，还可以执行下面的SQL语句，查看某个数据库下有哪些模式：
SELECT catalog_name, schema_name, schema_owner FROM information_schema.schemata;
musicdb=> SELECT catalog_name, schema_name, schema_owner FROM information_schema.schemata; catalog_name | schema_name | schema_owner --------------+--------------------+-------------- musicdb | pg_toast | omm musicdb | cstore | omm musicdb | pkg_service | omm musicdb | dbe_perf | omm musicdb | snapshot | omm musicdb | blockchain | omm musicdb | pg_catalog | omm musicdb | public | omm musicdb | sqladvisor | omm musicdb | dbe_pldebugger | omm musicdb | dbe_pldeveloper | omm musicdb | information_schema | omm musicdb | db4ai | omm musicdb | schm1 | user1 musicdb | schm2 | user1 musicdb | schm3 | user1 musicdb | schm4 | user1 (17 rows) musicdb=>
在数据库musicdb的不同的模式下创建同名的表：
–在不同模式下，创建相同的表
create table schm1.ttt(col varchar(100));
create table schm2.ttt(col varchar(100));
create table schm3.ttt(col varchar(100));
create table schm4.ttt(col varchar(100));
musicdb=> create table schm1.ttt(col varchar(100)); CREATE TABLE musicdb=> create table schm2.ttt(col varchar(100)); CREATE TABLE musicdb=> create table schm3.ttt(col varchar(100)); CREATE TABLE musicdb=> create table schm4.ttt(col varchar(100)); CREATE TABLE
–执行下面的SQL语句，往4个模式中的表ttt分别插入一条数据：
–在同一个数据库下，可以直接使用SchemaName.TableName来指定一个表，可以省略数据库名。
insert into schm1.ttt values(‘Hello! from schema schm1 11111’);
insert into schm2.ttt values(‘Hello! from schema schm2 22222’);
insert into schm3.ttt values(‘Hello! from schema schm3 33333’);
insert into schm4.ttt values(‘Hello! from schema schm4 44444’);
musicdb=> insert into schm1.ttt values('Hello! from schema schm1 11111');
INSERT 0 1
musicdb=> insert into schm2.ttt values('Hello! from schema schm2 22222');
INSERT 0 1
musicdb=> insert into schm3.ttt values('Hello! from schema schm3 33333');
INSERT 0 1
musicdb=> insert into schm4.ttt values('Hello! from schema schm4 44444');
INSERT 0 1
–执行下面的SQL语句，查看musicdb数据库目前有哪些表
–创建视图：
create or replace view my_tables as select table_catalog, table_schema, table_name, table_type from information_schema.tables where table_schema not in (‘pg_catalog’, ‘information_schema’,‘dbe_perf’);
musicdb=> create or replace view my_tables as select table_catalog, table_schema, table_name, table_type from informatema.tables where table_schema not in ('pg_catalog', 'information_schema','dbe_perf');
CREATE VIEW
musicdb=>
–查看视图：
select * from my_tables;
musicdb=> select * from my_tables; musicdb | public | my_tables | VIEW musicdb | schm4 | ttt | BASE TABLE musicdb | schm3 | ttt | BASE TABLE musicdb | schm2 | ttt | BASE TABLE musicdb | schm1 | ttt | BASE TABLE (8 rows) musicdb=> table_catalog | table_schema | table_name | table_type ---------------+-----------------+------------+------------ musicdb | db4ai | snapshot | BASE TABLE musicdb | dbe_pldeveloper | gs_errors | BASE TABLE musicdb | dbe_pldeveloper | gs_source | BASE TABLE musicdb=>
查看用户在数据库中搜索模式的顺序：
–查看默认的搜索模式的顺序
show SEARCH_PATH;
musicdb=> show SEARCH_PATH;
search_path
----------------
"$user",public
(1 row)
–访问musicdb数据库下其他模式的表，需要指定模式名前缀：
select * from schm1.ttt;
select * from schm2.ttt;
select * from schm3.ttt;
select * from schm4.ttt;
musicdb=> select * from schm1.ttt; col ---------------------------------- Hello! from schema schm1 11111 (1 row) musicdb=> select * from schm2.ttt; musicdb=> col ---------------------------------- Hello! from schema schm2 22222 (1 row) musicdb=> select * from schm3.ttt; musicdb=> col ---------------------------------- Hello! from schema schm3 33333 (1 row) musicdb=> musicdb=> select * from schm4.ttt; col ---------------------------------- Hello! from schema schm4 44444 (1 row) musicdb=>
模式是在数据库层面，用户是在实例层面
–登录musicdb数据库，查看用户和模式
gsql -d musicdb -U user1 -p 5432 -W kunpeng@1234 -r
\du
\dn
\q
omm@modb:~$ gsql -d musicdb -U user1 -p 5432 -W kunpeng@1234 -r
gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.
musicdb=> \du
List of roles
Role name | Attributes
| Member of
-----------+-----------------------------------------------------------------------------------------------------------------
-+-----------
gaussdb | Sysadmin
| {}
omm | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policyadmin, UseFT
| {}
user1 | Sysadmin
| {}
musicdb=> \dn
List of schemas
Name | Owner
-----------------+-------
blockchain | omm
cstore | omm
db4ai | omm
dbe_perf | omm
dbe_pldebugger | omm
dbe_pldeveloper | omm
pkg_service | omm
public | omm
schm1 | user1
schm2 | user1
schm3 | user1
schm4 | user1
snapshot | omm
sqladvisor | omm
(14 rows)
musicdb=> \q
–登录omm数据库，查看用户和模式
gsql -r
\du
\dn
\q
omm@modb:~$ gsql -r
gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.
omm=# \du
List of roles
Role name | Attributes
| Member of
-----------+-----------------------------------------------------------------------------------------------------------------
-+-----------
gaussdb | Sysadmin
| {}
omm | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policyadmin, UseFT
| {}
user1 | Sysadmin
| {}
omm=# \dn
List of schemas
Name | Owner
-----------------+-------
blockchain | omm
cstore | omm
db4ai | omm
dbe_perf | omm
dbe_pldebugger | omm
dbe_pldeveloper | omm
pkg_service | omm
public | omm
snapshot | omm
sqladvisor | omm
user1 | user1
(11 rows)
omm=# \q
omm@modb:~$
课程作业
查看当前数据库下有哪些模式
omm=# \dn
List of schemas
Name | Owner
-----------------+-------
blockchain | omm
cstore | omm
db4ai | omm
dbe_perf | omm
dbe_pldebugger | omm
dbe_pldeveloper | omm
pkg_service | omm
public | omm
snapshot | omm
sqladvisor | omm
user1 | user1
(11 rows)
omm=#
然后为数据库musicdb创建4个模式，名称自定义
musicdb=> create schema schm1 AUTHORIZATION user1; CREATE SCHEMA musicdb=> create schema schm2 AUTHORIZATION user1; CREATE SCHEMA musicdb=> create schema schm3 AUTHORIZATION user1; CREATE SCHEMA musicdb=> create schema schm4 AUTHORIZATION user1; CREATE SCHEMA musicdb=>
在数据库musicdb的不同的模式下创建同名的表
musicdb=> create table schm1.ttt(col varchar(100)); CREATE TABLE musicdb=> create table schm2.ttt(col varchar(100)); CREATE TABLE musicdb=> create table schm3.ttt(col varchar(100)); CREATE TABLE musicdb=> create table schm4.ttt(col varchar(100)); CREATE TABLE
访问musicdb数据库下不同模式的同名表
musicdb=> select * from schm1.ttt; col ---------------------------------- Hello! from schema schm1 11111 (1 row) musicdb=> select * from schm2.ttt; musicdb=> col ---------------------------------- Hello! from schema schm2 22222 (1 row) musicdb=> select * from schm3.ttt; musicdb=> col ---------------------------------- Hello! from schema schm3 33333 (1 row) musicdb=> musicdb=> select * from schm4.ttt; col ---------------------------------- Hello! from schema schm4 44444 (1 row) musicdb=>
实验理解：模式是在数据库层面，用户是在实例层面
omm@modb:~$ gsql -d musicdb -U user1 -p 5432 -W kunpeng@1234 -r
gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.
musicdb=> \du
List of roles
Role name | Attributes
| Member of
-----------+-----------------------------------------------------------------------------------------------------------------
-+-----------
gaussdb | Sysadmin
| {}
omm | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policyadmin, UseFT
| {}
user1 | Sysadmin
| {}
musicdb=> \dn
List of schemas
Name | Owner
-----------------+-------
blockchain | omm
cstore | omm
db4ai | omm
dbe_perf | omm
dbe_pldebugger | omm
dbe_pldeveloper | omm
pkg_service | omm
public | omm
schm1 | user1
schm2 | user1
schm3 | user1
schm4 | user1
snapshot | omm
sqladvisor | omm
(14 rows)
musicdb=> \q
omm@modb:~$ gsql -r
gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.
omm=# \du
List of roles
Role name | Attributes
| Member of
-----------+-----------------------------------------------------------------------------------------------------------------
-+-----------
gaussdb | Sysadmin
| {}
omm | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policyadmin, UseFT
| {}
user1 | Sysadmin
| {}
omm=# \dn
List of schemas
Name | Owner
-----------------+-------
blockchain | omm
cstore | omm
db4ai | omm
dbe_perf | omm
dbe_pldebugger | omm
dbe_pldeveloper | omm
pkg_service | omm
public | omm
snapshot | omm
sqladvisor | omm
user1 | user1
(11 rows)
omm=# \q
omm@modb:~$
课程学习体会
通过本次的实训操作，学会了创建数据库的模式并查看不同模式的表，理解模式是在数据库层面，用户是在实例层面。
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