今天来学习一下数据库创建，修改等相关操作
1.登录DB
Welcome to 墨天轮.
This is Web Terminal of modb.pro; Good Good Study, Day Day Up.
root@modb:~# su - omm
omm@modb:~$ gsql -r
gsql ((openGauss 2.0.0 build 78689da9) compiled at 2021-03-31 21:03:52 commit 0 last mr )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.
2.列出所有DB
omm=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+-------+----------+-------------+-------------+-------------------
omm | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
postgres | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
template0 | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/omm +
| | | | | omm=CTc/omm
template1 | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/omm +
| | | | | omm=CTc/omm
(4 rows)
3.创建一个新的DB名为music
omm=# create database music;
CREATE DATABASE
查看所有DB列表
omm=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+-------+----------+-------------+-------------+-------------------
music | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
omm | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
postgres | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
template0 | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/omm +
| | | | | omm=CTc/omm
template1 | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/omm +
| | | | | omm=CTc/omm
(5 rows)
4.修改数据库music的最大连接数为10
omm=# ALTER DATABASE music CONNECTION LIMIT= 10;
ALTER DATABASE
5.修改数据库名称进行重命名
omm=# ALTER DATABASE music RENAME TO music1;
ALTER DATABASE
omm=#
omm=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+-------+----------+-------------+-------------+-------------------
music1 | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
omm | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
postgres | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
template0 | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/omm +
| | | | | omm=CTc/omm
template1 | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/omm +
| | | | | omm=CTc/omm
(5 rows)
6.删除数据库
omm=# drop database music1;
DROP DATABASE
7.创建数据库名为music2
omm=# CREATE DATABASE music2;
CREATE DATABASE
8.切换当前数据库为music2
omm=# \c music2;
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "music2" as user "omm".
9.在music2数据库创建表t2
music2=# CREATE TABLE t2(a int, b varchar(10));
CREATE TABLE
music2=#
10.退出数据库
music2=# \q
omm@modb:~$
作业
omm@modb:~$ gsql -r
gsql ((openGauss 2.0.0 build 78689da9) compiled at 2021-03-31 21:03:52 commit 0 last mr )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.
omm=# create database tpcc1;
CREATE DATABASE
omm=# create database tpcc2;
CREATE DATABASE
omm=# alter database tpcc1 rename to tpcc10;
ALTER DATABASE
omm=#
omm=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+-------+----------+-------------+-------------+-------------------
music2 | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
omm | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
postgres | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
template0 | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/omm +
| | | | | omm=CTc/omm
template1 | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/omm +
| | | | | omm=CTc/omm
tpcc10 | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
tpcc2 | omm | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
(7 rows)
omm=# \c tpcc2
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "tpcc2" as user "omm".
tpcc2=# create table customer(id integer,name varchar(20));
CREATE TABLE
tpcc2=# drop database tpcc10;
DROP DATABASE
tpcc2=# drop database tpcc2;
ERROR: cannot drop the currently open database
tpcc2=# \c omm
Non-SSL connection (SSL connection is recommended when requiring high-security)
You are now connected to database "omm" as user "omm".
omm=# drop database tpcc2;
DROP DATABASE
omm=# \q
