openGauss之gsql工具的使用

课程学习内容

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。

数据库工具学习内容

使用gsql命令连接数据库

root@modb:~# 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=# 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=# \q 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=# 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=#

在gsql中查看数据库的版本

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)

在gsql中查看数据库pg基础版本

omm=# show server_version; server_version ---------------- 9.2.4 (1 row)

在gsql中查看数据库版权信息

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 | 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 (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". omm=#

–\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 openGauss-# Non-SSL connection (SSL connection is recommended when requiring high-security) You are now connected to database "postgres" as user "omm". openGauss-#

–\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。

openGauss-# \du List of roles Role name | Attributes | Member of -----------+--------------------------------------------------------------------------------------------------------------- ---+----------- gaussdb | Sysadmin | {} omm | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policyadmin, Use FT | {} openGauss-# \dg List of roles Role name | Attributes | Member of -----------+--------------------------------------------------------------------------------------------------------------- ---+----------- gaussdb | Sysadmin | {} omm | Sysadmin, Create role, Create DB, Replication, Administer audit, Monitoradmin, Operatoradmin, Policyadmin, Use FT | {} openGauss-#

–\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。

–\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。

–创建表

openGauss=# CREATE TABLE customer_t(c_customer_sk integer,c_customer_id char(5),c_first_name char(6),c_last_name char(8)); CREATE TABLE openGauss=#

–插入数据

openGauss=# INSERT INTO customer_t (c_customer_sk, c_customer_id, c_first_name,c_last_name) VALUES (3769, 5, 'G');e','White' INSERT 0 1 openGauss=#

–\dt命令，命令\dt的作用是显示数据库中所有的表。

openGauss=# \dt List of relations Schema | Name | Type | Owner | Storage --------+------------+-------+-------+---------------------------------- public | customer_t | table | omm | {orientation=row,compression=no} (1 row) openGauss=#

–\d TableName命令，元命令\d TableName的作用是查看某个表的信息。

–\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。

–可以用\pset命令以不同的方法显示表：

–打开扩展表格式模式。

openGauss=# \x Expanded display is off. openGauss=# \x Expanded display is on. openGauss=#

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

openGauss=# show AUTOCOMMIT; +-[ RECORD 1 ]----+ | autocommit | on | +------------+----+ openGauss=#

–测试gsql中事务默认为自动提交功能

openGauss=# create table customer_new as select * from customer_t; INSERT 0 1 openGauss=# \q omm@modb:~$

–重新登录后看到之前创建的表customer_new：

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=# \dt public | customer_t | table | omm | {orientation=row,compression=no} (2 rows) openGauss=# List of relations Schema | Name | Type | Owner | Storage --------+--------------+-------+-------+---------------------------------- public | customer_new | table | omm | {orientation=row,compression=no} openGauss=#

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！

openGauss=# \set AUTOCOMMIT off openGauss=#

–插入一些数据

openGauss=# INSERT INTO customer_t (c_customer_sk, c_customer_id, c_first_name,c_last_name) VALUES openGauss-# (6885, 1, 'Joes', 'Hunter'), openGauss-# (4321, 2, 'Lily','Carter'), openGauss-# (9527, 3, 'James', 'Cook'), openGauss-# (9500, 4, 'Lucy', 'Baker'); INSERT 0 4 openGauss=#

–查看表中数据

–执行回滚

openGauss=# ROLLBACK; ROLLBACK openGauss=#

–检查是否回滚成功

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。

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) Output format options: -A, --no-align unaligned table output mode -F, --field-separator=STRING set field separator (default: "|") -H, --html HTML table output mode -P, --pset=VAR[=ARG] set printing option VAR to ARG (see \pset command) -R, --record-separator=STRING set record separator (default: newline) -r if this parameter is set,use libedit -t, --tuples-only print rows only -T, --table-attr=TEXT set HTML table tag attributes (e.g., width, border) -x, --expanded turn on expanded table output -z, --field-separator-zero set field separator to zero byte -0, --record-separator-zero -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) set record separator to zero byte -2, --pipeline use pipeline to pass the password, forbidden to use in terminal must use with -c or -f Connection options: -h, --host=HOSTNAME database server host or socket directory (default: "local socket") allow multi host IP address with comma separator in centralized cluster -p, --port=PORT database server port (default: "5432") -U, --username=USERNAME database user name (default: "omm") -W, --password=PASSWORD the password of specified database user For more information, type "\?" (for internal commands) or "\help" (for SQL commands) from within gsql, or consult the gsql section in the openGauss documentation. omm@modb:~$

–\h获取和SQL语法有关的帮助信息

openGauss=# \h Available help: ABORT CREATE DATA SOURCE DROP NODE GROUP ALTER DATA SOURCE CREATE FOREIGN TABLE DROP PACKAGE BODY ALTER DATABASE CREATE FUNCTION DROP PROCEDURE ALTER DEFAULT PRIVILEGES CREATE GROUP DROP PUBLICATION ALTER DIRECTORY CREATE INDEX DROP RESOURCE LABEL 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 GLOBAL CONFIGURATION CREATE NODE DROP SEQUENCE ALTER GROUP CREATE NODE GROUP DROP SERVER ALTER EXTENSION CREATE LANGUAGE DROP RESOURCE POOL ALTER FOREIGN TABLE CREATE MASKING POLICY DROP ROLE ALTER INDEX CREATE OPERATOR DROP SUBSCRIPTION ALTER LARGE OBJECT CREATE PACKAGE DROP SYNONYM ALTER MASKING POLICY CREATE PACKAGE BODY DROP TABLE ALTER MATERIALIZED VIEW CREATE PROCEDURE DROP TABLESPACE ALTER NODE CREATE PUBLICATION DROP TEXT SEARCH CONFIGURATION ALTER FOREIGN TABLE FOR HDFS CREATE MATERIALIZED VIEW DROP ROW LEVEL SECURITY POLICY ALTER FUNCTION CREATE MODEL DROP SCHEMA ALTER NODE GROUP CREATE RESOURCE LABEL DROP TEXT SEARCH DICTIONARY ALTER OPERATOR CREATE RESOURCE POOL DROP TRIGGER ALTER PACKAGE CREATE ROLE DROP TYPE ALTER PUBLICATION CREATE ROW LEVEL SECURITY POLICY DROP USER ALTER RESOURCE LABEL CREATE SCHEMA DROP VIEW ALTER RESOURCE POOL CREATE SEQUENCE DROP WEAK PASSWORD DICTIONARY ALTER ROLE CREATE SERVER DROP WORKLOAD GROUP ALTER ROW LEVEL SECURITY POLICY CREATE SNAPSHOT AS END --More--

–? 获取和元命令有关的帮助信息

openGauss=# \? 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 Input/Output \copy ... perform SQL COPY with data stream to the client host \echo [STRING] write string to standard output \i FILE execute commands from file \p show the contents of the query buffer \r reset (clear) the query buffer \w FILE write query buffer to file \ir+ FILE KEY as \i+, but relative to location of current script \o [FILE] send all query results to file or |pipe \qecho [STRING] write string to query output stream (see \o) --More-- \i+ FILE KEY execute commands from encrypted file \ir FILE as \i, but relative to location of current script Informational --More--

课程学习心得

通过本次实训操作，学会了用gsql工具来连接数据库，查看数据库版本信息、版权信息和常见元命令使用等。