学习目标
学习openGauss数据库客户端工具gsql的使用。
课程学习
gsql是openGauss提供在命令行下运行的数据库连接工具，可以通过此工具连接服务器并对其进行操作和维护，除了具备操作数据库的基本功能，gsql还提供了若干高级特性，便于用户使用。
1.使用gsql命令连接数据库
--使用omm用户连接到本机omm数据库的5432端口，命令中的-r选项提供了对gsql命令的历史版本支持。
root@modb:~# su - omm
omm@modb:~$ gsql -d omm -p 5432 -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.
2.在gsql中查看数据库的版本、pg基础版本和版权信息
omm=# select version();
version
-------------------------------------------------------------------------------------------------------------------
------------------------------------
(openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr on aarch64-unknown-linux-gnu,
compiled by g++ (GCC) 7.3.0, 64-bit
(1 row)
omm=# show server_version;
server_version
----------------
9.2.4
(1 row)
omm=# \copyright
GaussDB Kernel Database Management System
Copyright (c) Huawei Technologies Co., Ltd. 2018. All rights reserved.
3.常见元命令的使用
--\l命令，元命令\l的作用是显示openGauss数据库集簇中，目前有哪些数据库。omm=# \l List of databases Name | Owner | Encoding | Collate | Ctype | Access privileges -----------+-------+----------+---------+-------+------------------- 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=# | | | | | omm=CTc/omm (4 rows)--\conninfo命令，元命令\conninfo的作用是在gsql中，显示会话的连接信息。omm-# \conninfo You are connected to database "omm" as user "omm" via socket in "/tmp" at port "5432".--\c[onnect] [DBNAME]命令，元命令\ c[onnect] [DBNAME]的作用是在gsql中，切换连接的数据库postgres。omm-# \c postgres Non-SSL connection (SSL connection is recommended when requiring high-security) You are now connected to database "postgres" as user "omm".--\du命令和\dg命令，元命令\dg命令与元命令\du命令的作用类似，都是显示openGauss数据库集簇中，目前有哪些用户和角色。omm=# \du List of roles Role name | Attributes | Member of -----------+------------------------------------------------------------------------------------------------------- -----------+----------- gaussdb | Sysadmin | {} omm | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policyad min, UseFT | {} omm=# \dg List of roles Role name | Attributes | Member of -----------+------------------------------------------------------------------------------------------------------- -----------+----------- gaussdb | Sysadmin | {} omm | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policyad min, UseFT | {}--\db命令，元命令\db的作用是显示openGauss数据库集簇中，目前有哪些表空间。omm=# \db List of tablespaces Name | Owner | Location ------------+-------+---------- pg_default | omm | pg_global | omm | (2 rows)--\dn命令，元命令\dn的作用是显示当前数据库有哪些数据库模式。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 (10 rows)--创建表并插入数据omm=# CREATE TABLE customer_t omm-# ( c_customer_sk integer, omm(# c_customer_id char(5), omm(# c_first_name char(6), omm(# c_last_name char(8) omm(# ) ; CREATE TABLE omm=# INSERT INTO customer_t (c_customer_sk, c_customer_id, c_first_name,c_last_name) VALUES (3769, 5, 'Grace','White'); INSERT 0 1--\dt命令，命令\dt的作用是显示数据库中所有的表。omm=# \dt List of relations Schema | Name | Type | Owner | Storage --------+------------+-------+-------+---------------------------------- public | customer_t | table | omm | {orientation=row,compression=no} (1 row) --\d TableName命令，元命令\d TableName的作用是查看某个表的信息。 omm=# \d customer_t Table "public.customer_t" Column | Type | Modifiers ---------------+--------------+----------- c_customer_sk | integer | c_customer_id | character(5) | c_first_name | character(6) | c_last_name | character(8) |--\di IndexName命令，查看索引信息，元命令\di IndexName的作用是查看某个索引的信息。omm=# create index idx_customer_id on customer_t(c_customer_id); #创建一个索引 CREATE INDEX omm=# \di List of relations Schema | Name | Type | Owner | Table | Storage --------+-----------------+-------+-------+------------+--------- public | idx_customer_id | index | omm | customer_t | (1 row)--可以用\pset命令以不同的方法显示表：omm=# \pset border 2 #设置输出格式为里外都有表格 Border style is 2. omm=# SELECT * FROM customer_t; +---------------+---------------+--------------+-------------+ | c_customer_sk | c_customer_id | c_first_name | c_last_name | +---------------+---------------+--------------+-------------+ | 3769 | 5 | Grace | White | +---------------+---------------+--------------+-------------+ (1 row)--打开扩展表格式模式。omm=# \x #把表中每一行的每列数据都拆分为单行展示。 Expanded display is on. omm=# SELECT * FROM customer_t; +---------------+----------+ omm=# +-[ RECORD 1 ]--+----------+ | c_customer_sk | 3769 | | c_customer_id | 5 | | c_first_name | Grace | | c_last_name | White |
4.gsql中的事务：测试gsql中的默认事务自动提交功能
--查看gsql中事务是否默认为自动提交omm=# show AUTOCOMMIT; +-[ RECORD 1 ]----+ | autocommit | on | +------------+----+--测试gsql中事务默认为自动提交功能omm=# create table customer_new as select * from customer_t; #在旧表基础上复制一张新表（不含主键等） INSERT 0 1 omm=# \q--重新登录后看到之前创建的表customer_new：omm@modb:~$ gsql -d omm -p 5432 -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=# \dt List of relations Schema | Name | Type | Owner | Storage --------+--------------+-------+-------+---------------------------------- public | customer_new | table | omm | {orientation=row,compression=no} public | customer_t | table | omm | {orientation=row,compression=no} (2 rows)
5.gsql中的事务：测试gsql中的事务手动提交功能
–测试gsql手动提交#Opengauss默认执行完一条语句后，立即提交。可以关闭自动提交功能： #注意：此处设置ATUOCOMMIT必须用大写！omm=# \echo :AUTOCOMMIT; on; omm=# \set AUTOCOMMIT off #关掉自动提交 omm=# \echo :AUTOCOMMIT; off; omm=# omm-# INSERT INTO customer_t (c_customer_sk, c_customer_id, c_first_name,c_last_name) VALUES (6885, 1, 'Joes', 'Hunter'), omm-# omm-# (4321, 2, 'Lily','Carter'), omm-# (9527, 3, 'James', 'Cook'), (9500, 4, 'Lucy', 'Baker'); INSERT 0 4 omm=# select * from customer_t; c_customer_sk | c_customer_id | c_first_name | c_last_name ---------------+---------------+--------------+------------- 3769 | 5 | Grace | White 6885 | 1 | Joes | Hunter 4321 | 2 | Lily | Carter 9527 | 3 | James | Cook 9500 | 4 | Lucy | Baker (5 rows)omm=# rollback; 回滚 ROLLBACK omm=# select * from customer_t; (1 row) omm=# c_customer_sk | c_customer_id | c_first_name | c_last_name ---------------+---------------+--------------+------------- 3769 | 5 | Grace | White
6.gsql相关的帮助
--连接数据库时，可以使用如下命令获取帮助信息。(登录数据库之前使用) omm=# gsql --help omm-# \q omm@modb:~$ gsql --help gsql is the openGauss interactive terminal. Usage: gsql [OPTION]... [DBNAME [USERNAME]] General options: -c, --command=COMMAND run only single command (SQL or internal) and exit -d, --dbname=DBNAME database name to connect to (default: "omm") -f, --file=FILENAME execute commands from file, then exit -l, --list list available databases, then exit -v, --set=, --variable=NAME=VALUE set gsql variable NAME to VALUE -V, --version output version information, then exit -X, --no-gsqlrc do not read startup file (~/.gsqlrc) -1 ("one"), --single-transaction execute command file as a single transaction -?, --help show this help, then exit Input and output options: -a, --echo-all echo all input from script -e, --echo-queries echo commands sent to server -E, --echo-hidden display queries that internal commands generate -k, --with-key=KEY the key for decrypting the encrypted file -L, --log-file=FILENAME send session log to file -m, --maintenance can connect to cluster during 2-pc transaction recovery -n, --no-libedit disable enhanced command line editing (libedit) -o, --output=FILENAME send query results to file (or |pipe) -q, --quiet run quietly (no messages, only query output) -C, --enable-client-encryption enable client encryption feature -s, --single-step single-step mode (confirm each query) -S, --single-line single-line mode (end of line terminates SQL command) 。。。 --\h获取和SQL语法有关的帮助信息 omm-# \h Available help: ABORT CREATE DATA SOURCE DROP NODE GROUP ALTER APP WORKLOAD GROUP CREATE DATABASE DROP OPERATOR ALTER APP WORKLOAD GROUP MAPPING CREATE DIRECTORY DROP OWNED ALTER AUDIT POLICY CREATE EXTENSION DROP PACKAGE ALTER DATA SOURCE CREATE FOREIGN TABLE DROP PACKAGE BODY ALTER FUNCTION CREATE MODEL DROP SCHEMA ALTER GLOBAL CONFIGURATION CREATE NODE DROP SEQUENCE ALTER GROUP CREATE NODE GROUP DROP SERVER ALTER DATABASE CREATE FUNCTION DROP PROCEDURE ALTER DEFAULT PRIVILEGES CREATE GROUP DROP PUBLICATION ALTER DIRECTORY CREATE INDEX DROP RESOURCE LABEL ALTER EXTENSION CREATE LANGUAGE DROP RESOURCE POOL ALTER FOREIGN TABLE CREATE MASKING POLICY DROP ROLE ALTER FOREIGN TABLE FOR HDFS CREATE MATERIALIZED VIEW DROP ROW LEVEL SECURITY POLICY ALTER INDEX CREATE OPERATOR DROP SUBSCRIPTION ... --\? 获取和元命令有关的帮助信息omm-# \? General \copyright show openGauss usage and distribution terms \g [FILE] or ; execute query (and send results to file or |pipe) \h(\help) [NAME] help on syntax of SQL commands, * for all commands \parallel [on [num]|off] toggle status of execute (currently off) \q quit gsql Query Buffer \e [FILE] [LINE] edit the query buffer (or file) with external editor \ef [FUNCNAME [LINE]] edit function definition with external editor \p show the contents of the query buffer \copy ... perform SQL COPY with data stream to the client host \echo [STRING] write string to standard output \ir FILE as \i, but relative to location of current script \ir+ FILE KEY as \i+, but relative to location of current script \i FILE execute commands from file \i+ FILE KEY execute commands from encrypted file \o [FILE] send all query results to file or |pipe \qecho [STRING] write string to query output stream (see \o) --More-- \r reset (clear) the query buffer \w FILE write query buffer to file...
课程作业
1.gsql命令连到数据库omm
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.root@modb:~# su - omm omm@modb:~$ gsql -d omm -p 5432 -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.
2.查看数据库的版本、版权信息
select version(); #数据库版本
show server_version; #pg基础版本
\copyright #版权信息
3.常见元命令使用
--\l命令，元命令\l的作用是显示openGauss数据库集簇中，目前有哪些数据库。
\l
--\conninfo命令，元命令\conninfo的作用是在gsql中，显示会话的连接信息。
\conninfo
--\c[onnect] [DBNAME]命令，元命令\ c[onnect] [DBNAME]的作用是在gsql中，切换连接的数据库postgres。
\c postgres
--\du命令和\dg命令，元命令\dg命令与元命令\du命令的作用类似，都是显示openGauss数据库集簇中，目前有哪些用户和角色。
\du
\dg
--\db命令，元命令\db的作用是显示openGauss数据库集簇中，目前有哪些表空间。
\db
--\dn命令，元命令\dn的作用是显示当前数据库有哪些数据库模式。
\dn
--创建表
CREATE TABLE customer_t
( c_customer_sk integer,
c_customer_id char(5),
c_first_name char(6),
c_last_name char(8)
) ;
--插入数据
INSERT INTO customer_t (c_customer_sk, c_customer_id, c_first_name,c_last_name) VALUES (3769, 5, 'Grace','White');
--\dt命令，命令\dt的作用是显示数据库中所有的表。
\dt
--\d TableName命令，元命令\d TableName的作用是查看某个表的信息。
\d customer_t
--\di IndexName命令，查看索引信息，元命令\di IndexName的作用是查看某个索引的信息。
create index idx_customer_id on customer_t(c_customer_id);
\di
--可以用\pset命令以不同的方法显示表：
\pset border 2 #内外都有框
SELECT * FROM customer_t;
--打开扩展表格式模式。
\x #一行一行显示单列4.使用两种方法，连到postgres数据库中
root@modb:~# su - omm omm@modb:~$ gsql -d postgres -p 5432 -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. openGauss=# \conninfo You are connected to database "postgres" as user "omm" via socket in "/tmp" at port "5432".root@modb:~# su - omm omm@modb:~$ gsql -d omm -p 5432 -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=# \c postgres Non-SSL connection (SSL connection is recommended when requiring high-security) You are now connected to database "postgres" as user "omm". openGauss=# \conninfo You are connected to database "postgres" as user "omm" via socket in "/tmp" at port "5432".
5.测试gsql中的默认事务自动提交功能
--查看gsql中事务是否默认为自动提交
show AUTOCOMMIT;
--测试gsql中事务默认为自动提交功能
create table customer_new as select * from customer_t;
\q
--重新登录后看到之前创建的表customer_new：
gsql -d postgres -p 5432 -r
\dt
6.测试gsql中的事务手动提交功能
#测试gsql手动提交
#Opengauss默认执行完一条语句后，立即提交。可以关闭自动提交功能：
#注意：此处设置ATUOCOMMIT必须用大写！
\echo : AUTOCOMMIT; #查看自动提交状态
\set AUTOCOMMIT off #关闭自动提交
#插入一些数据
INSERT INTO customer_t (c_customer_sk, c_customer_id, c_first_name,c_last_name) VALUES
(6885, 1, 'Joes', 'Hunter'),
(4321, 2, 'Lily','Carter'),
(9527, 3, 'James', 'Cook'),
(9500, 4, 'Lucy', 'Baker');
#查看表中数据
select * from customer_t;
--执行回滚
ROLLBACK;
--检查是否回滚成功
select * from customer_t;
7.了解gsql相关帮助
#连接数据库时，可以使用如下命令获取帮助信息。（在登陆数据库之前使用）
gsql --help
#\h获取和SQL语法有关的帮助信息
\h
#\? 获取和元命令有关的帮助信息
\？
「喜欢这篇文章，您的关注和赞赏是给作者最好的鼓励」
关注作者
【版权声明】本文为墨天轮用户原创内容，转载时必须标注文章的来源（墨天轮），文章链接，文章作者等基本信息，否则作者和墨天轮有权追究责任。如果您发现墨天轮中有涉嫌抄袭或者侵权的内容，欢迎发送邮件至：contact@modb.pro进行举报，并提供相关证据，一经查实，墨天轮将立刻删除相关内容。
