PostgreSQL快速入门:psql工具的使用
一、psql介绍 psql是PostgreSQL中的一个命令行交互式客户端工具,类似Oracle中的命令行工具sqlplus:1.允许你交互地键入SQL或命令,然后把它们发出给PostgreSQL服务器,再显示SQL或命令的结果;2.输入的内容还可以来自一个文件;3.还提供了一些元命令和多种类似shell的特性来实现书写脚本,以及对对量任务的自动化工作;二、psql的简单实用按照前面的步骤,切换su - postgres用户,实用psql工具连接数据库。1.查看有哪些数据库
a.安装好后,默认会有一个叫postgres的数据库,还有两个模板数据库template0和template1;b.用户再建数据库的时候,默认是从模板数据库template1克隆出来;c.template0是一个最简化的模板库,创建数据库时,如果明确指定从此数据库集成,将创建一个最简化的数据库;2.创建数据库osdba
postgres=# CREATE DATABASE osdba; CREATE DATABASE postgres-# l List of databases Name | Owner | Encoding | Collation | Ctype | Access privileges -----------+----------+----------+-------------+-------------+----------------------- osdba | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | postgres | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | template0 | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres : postgres=CTc/postgres template1 | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres : postgres=CTc/postgres (4 rows) 3.访问osdba数据库 -bash-4.1$ psql osdba psql (8.4.20) Type "help" for help. 4.在数据库osdba中创建表t
osdba=# create table t(id int primary key,name varchar(40)); NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "t_pkey" for table "t" CREATE TABLE 5.查看osdb数据库中的表
osdba=# d List of relations Schema | Name | Type | Owner --------+------+-------+---------- public | t | table | postgres (1 row) 6.创建数据库testdb后,并连接到testdb数据库
osdba=# CREATE DATABASE testdb; CREATE DATABASE osdba=# c testdb psql (8.4.20) You are now connected to database "testdb". testdb=# 三、psql的常用命令1.d命令-查看当前数据库中的所有表
osdba-# d List of relations Schema | Name | Type | Owner --------+------+-------+---------- public | t | table | postgres (1 row) 2.d命令-跟一个表命,查看这个表的结构定义
osdba-# d t Table "public.t" Column | Type | Modifiers --------+-----------------------+----------- id | integer | not null name | character varying(40) | Indexes: "t_pkey" PRIMARY KEY,btree (id) 3.d命令-可以查看表格t的索引信息
osdba-# d t_pkey Index "public.t_pkey" Column | Type --------+--------- id | integer primary key,btree,for table "public.t" 4.d命令-跟通配符如*或?
osdba-# d t* Table "public.t" Column | Type | Modifiers --------+-----------------------+----------- id | integer | not null name | character varying(40) | Indexes: "t_pkey" PRIMARY KEY,btree (id) Index "public.t_pkey" Column | Type --------+--------- id | integer primary key,sans-serif; line-height: 15px;">5.d+命令,显示比d命令更加详细的信息,显示与表列关联的注释 osdba-# d+ List of relations Schema | Name | Type | Owner | Size | Description --------+------+-------+----------+---------+------------- public | t | table | postgres | 0 bytes | (1 row) 6.匹配不同对象类型的d命令,如dt-只想显示匹配的表;di-只想显示索引;ds-只显示序列;dv-只显示视图;df-只显示函数等...
osdba-# dt t* List of relations Schema | Name | Type | Owner --------+------+-------+---------- public | t | table | postgres 7.dn命令-列出所有的schema
osdba-# dn List of schemas Name | Owner --------------------+---------- information_schema | postgres pg_catalog | postgres pg_toast_temp_1 | postgres public | postgres (5 rows) 8.db命令-显示所有表空间
osdba-# db List of tablespaces Name | Owner | Location ------------+----------+---------- pg_default | postgres | pg_global | postgres | (2 rows) 9.dg-列出数据库中所有角色和用户
osdba-# dg List of roles Role name | Attributes | Member of -----------+-------------+----------- postgres | Superuser | {} : Create role : Create DB10.dp-显示表的权限分配情况 osdba-# dp Access privileges Schema | Name | Type | Access privileges | Column access privileges --------+------+-------+-------------------+-------------------------- public | t | table | | (1 row) 四、指定字符集编译的命令1.encoding gbk-设置客户端的字符编码为gbk五、pset命令
1.pset命令-用于设置输出的格式,pset border 0/1/2:输出内容无边框、只有内边框、内外都有边框 osdba-# pset border 0 Border style is 0. osdba-# dp Access privileges Schema Name Type Access privileges Column access privileges ------ ---- ----- ----------------- ------------------------ public t table (1 row) osdba-# pset border 1 Border style is 1. osdba-# dp Access privileges Schema | Name | Type | Access privileges | Column access privileges --------+------+-------+-------------------+-------------------------- public | t | table | | (1 row) osdba-# pset border 2 Border style is 2. osdba-# dp Access privileges +--------+------+-------+-------------------+--------------------------+ | Schema | Name | Type | Access privileges | Column access privileges | +--------+------+-------+-------------------+--------------------------+ | public | t | table | | | +--------+------+-------+-------------------+--------------------------+ (1 row) 2.x命令-可以把表中的每一行的每列数据都拆分为单行展示,如果有一行数据有太多的拆行,显示不下,就可以使用这个命令
osdba-# x Expanded display is on. osdba-# dp Access privileges +-[ RECORD 1 ]-------------+--------+ | Schema | public | | Name | t | | Type | table | | Access privileges | | | Column access privileges | | +--------------------------+--------+ osdba-# x Expanded display is off. osdba-# dp Access privileges +--------+------+-------+-------------------+--------------------------+ | Schema | Name | Type | Access privileges | Column access privileges | +--------+------+-------+-------------------+--------------------------+ | public | t | table | | | +--------+------+-------+-------------------+--------------------------+ (1 row) 五、psql使用技巧1.使用上下键把过去使用过的命令或者SQL语句调出来,连续两个tab键表示补全或给出提示输入
osdba-# d d dc dD dew dFd dg dn ds dT da dC des df dFp di do dS du db dd deu dF dFt dl dp dt dv 2.psql加上-E参数,可以把psql中各种以""开头的命令执行的实际SQL打印出来
-bash-4.1$ psql -E postgres psql (8.4.20) Type "help" for help. postgres=# d ********* QUERY ********** SELECT n.nspname as "Schema",c.relname as "Name",CASE c.relkind WHEN 'r' THEN 'table' WHEN 'v' THEN 'view' WHEN 'i' THEN 'index' WHEN 'S' THEN 'sequence' WHEN 's' THEN 'special' END as "Type",pg_catalog.pg_get_userbyid(c.relowner) as "Owner" FROM pg_catalog.pg_class c LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace WHERE c.relkind IN ('r','v','S','') AND n.nspname <> 'pg_catalog' AND n.nspname <> 'information_schema' AND n.nspname !~ '^pg_toast' AND pg_catalog.pg_table_is_visible(c.oid) ORDER BY 1,2; ************************** No relations found 如果你在使用之后,想立即关闭
(编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |