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。 su - omm gsql -r 或 gsql -d omm -p 5432 -r
root@modb:~# 命令的历史版本支持。mm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 -bash: $'--\344\275\277\347\224\250omm\347\224\250\346\210\267\350\277\236\346\216\245\345\210\260\346\234\254\346\234\272omm\346\225\260\346\215\256\345\272\223\347\232\2045432\347\253\257\345\217\243\357\274\214\345\221\275\344\273\244\344\270\255\347\232\204-r\351\200\211\351\241\271\346\217\220\344\276\233\344\272\206\345\257\271gsql\345\221\275\344\273\244\347\232\204\345\216\206\345\217\262\347\211\210\346\234\254\346\224\257\346\214\201\343\200\202': command not found root@modb:~# su - omm omm@modb:~$ 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=# gsql -d omm -p 5432 -r omm-#
2. 在gsql中查看数据库的版本、pg基础版本和版权信息
select version(); show server_version; \copyright
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. omm=#
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。 \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 SELECT * FROM customer_t; --打开扩展表格式模式。 \x
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 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
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 omm=# omm=# show AUTOCOMMIT; autocommit ------------ on (1 row) omm=# --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; INSERT 0 1 omm=# \q omm@modb:~$ --重新登录后看到之前创建的表customer_new： -bash: $'--\351\207\215\346\226\260\347\231\273\345\275\225\345\220\216\347\234\213\345\210\260\344\271\213\345\211\215\345\210\233\345\273\272\347\232\204\350\241\250customer_new\357\274\232': command not found omm@modb:~$ 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 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) openGauss=#
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！ \set AUTOCOMMIT off --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;
openGauss=# \set AUTOCOMMIT off 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-# openGauss-# (9527, 3, 'James', 'Cook'), (9500, 4, 'Lucy', 'Baker'); INSERT 0 4 openGauss=# 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) openGauss=# ROLLBACK; openGauss=# ROLLBACK openGauss=# SELECT * FROM customer_t; (1 row) openGauss=# 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。 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 \？
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) Output format options: -A, --no-align unaligned table output mode -F, --field-separator=STRING -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 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: 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 -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:~$
openGauss=# \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 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 FUNCTION CREATE MODEL DROP SCHEMA ALTER GLOBAL CONFIGURATION CREATE NODE DROP SEQUENCE ALTER GROUP CREATE NODE GROUP DROP SERVER ALTER INDEX CREATE OPERATOR ALTER PACKAGE CREATE ROLE DROP TYPE --More-- 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 NODE GROUP CREATE RESOURCE LABEL DROP TEXT SEARCH DICTIONARY ALTER OPERATOR CREATE RESOURCE POOL DROP TRIGGER
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 \p show the contents of the query buffer \r reset (clear) the query buffer \w FILE write query buffer to file Input/Output \copy ... perform SQL COPY with data stream to the client host \i+ FILE KEY execute commands from encrypted file \ir FILE as \i, but relative to location of current script \echo [STRING] write string to standard output \i FILE execute commands from file \qecho [STRING] write string to query output stream (see \o) --More-- \ir+ FILE KEY as \i+, but relative to location of current script \o [FILE] send all query results to file or |pipe Informational (options: S = show system objects, + = additional detail) \d[S+] list tables, views, and sequences \d[S+] NAME describe table, view, sequence, or index \da[S] [PATTERN] list aggregates \db[+] [PATTERN] list tablespaces \dc[S+] [PATTERN] list conversions \dC[+] [PATTERN] list casts \dd[S] [PATTERN] show object descriptions not displayed elsewhere \ddp [PATTERN] list default privileges \dD[S+] [PATTERN] list domains \ded[+] [PATTERN] list data sources \det[+] [PATTERN] list foreign tables \des[+] [PATTERN] list foreign servers \deu[+] [PATTERN] list user mappings \dew[+] [PATTERN] list foreign-data wrappers \df[antw][S+] [PATRN] list [only agg/normal/trigger/window] functions \dF[+] [PATTERN] list text search configurations \dFd[+] [PATTERN] list text search dictionaries \dFp[+] [PATTERN] list text search parsers \dFt[+] [PATTERN] list text search templates \di[S+] [PATTERN] list indexes \dg[+] [PATTERN] list roles \dl list large objects, same as \lo_list \dL[S+] [PATTERN] list procedural languages \dm[S+] [PATTERN] list materialized views \dn[S+] [PATTERN] list schemas \do[S] [PATTERN] list operators \dO[S+] [PATTERN] list collations \dp [PATTERN] list table, view, and sequence access privileges \drds [PATRN1 [PATRN2]] list per-database role settings \ds[S+] [PATTERN] list sequences \dt[S+] [PATTERN] list tables \dT[S+] [PATTERN] list data types \du[+] [PATTERN] list roles \dv[S+] [PATTERN] list views \dE[S+] [PATTERN] list foreign tables \dx[+] [PATTERN] list extensions \l[+] list all databases \sf[+] FUNCNAME show a function's definition \z [PATTERN] same as \dp
