PostgreSQL精简命令:

dos命令行连接PostgreSQL:

1. 接入PostgreSQL数据库: psql -h IP地址 -p 端口 -U 用户名 -d 数据库名

2. 输入数据库密码

C:\Users\admin\Desktop
λ psql -U postgres -d yiibai_db
用户 postgres 的口令：
psql (11.1)
输入 "help" 来获取帮助信息.

yiibai_db=# \dt
                关联列表
 架构模式 |   名称   |  类型  |  拥有者
----------+----------+--------+----------
 public   | student  | 数据表 | postgres
 public   | student2 | 数据表 | postgres
(2 行记录)

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查看数据库:

1. SELECT datname FROM pg_database;
或者
2. psql命令行中执行:\l (反斜杠l)

例如:

yiibai_db=# SElECT datname FROM pg_database;
  datname
-----------
 postgres
 template1
 template0
 yiibai_db
(4 行记录)


yiibai_db=# \l
                                                                             数据库列表
   名称    |  拥有者  | 字元编码 |                      校对规则                       |                        Ct
ype                        |       存取权限
-----------+----------+----------+-----------------------------------------------------+-----------------------------------------------------+-----------------------
 postgres  | postgres | UTF8     | Chinese (Simplified)_People's Republic of China.936 | Chinese (Simplified)_People's Republic of China.936 |
 template0 | postgres | UTF8     | Chinese (Simplified)_People's Republic of China.936 | Chinese (Simplified)_People's Republic of China.936 | =c/postgres          +
           |          |          |                                                     |
                           | postgres=CTc/postgres
 template1 | postgres | UTF8     | Chinese (Simplified)_People's Republic of China.936 | Chinese (Simplified)_People's Republic of China.936 | =c/postgres          +
           |          |          |                                                     |
                           | postgres=CTc/postgres
 yiibai_db | postgres | UTF8     | Chinese (Simplified)_People's Republic of China.936 | Chinese (Simplified)_People's Republic of China.936 | =Tc/postgres         +
           |          |          |                                                     |
                           | postgres=CTc/postgres
(4 行记录)


yiibai_db=#

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切换数据库:

切换数据库：\c databasename

yiibai_db=# SElECT datname FROM pg_database;
  datname
-----------
 postgres
 template1
 template0
 yiibai_db
(4 行记录)


yiibai_db=# \c postgres;
您现在已经连接到数据库 "postgres",用户 "postgres".
postgres=#

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查看当前数据库中的表:

1. SELECT tablename FROM pg_tables WHERE schemaname='public';  # 列出数据库中用户自定义的表名
或者
2. psql>\dt

yiibai_db=# \dt
                关联列表
 架构模式 |   名称   |  类型  |  拥有者
----------+----------+--------+----------
 public   | student  | 数据表 | postgres
 public   | student2 | 数据表 | postgres
(2 行记录)


yiibai_db=# SELECT tablename FROM yiibai_db;
ERROR:  relation "yiibai_db" does not exist
第1行SELECT tablename FROM yiibai_db;
                           ^
yiibai_db=# SELECT tablename FROM pg_tables WHERE schemaname='public';
 tablename
-----------
 student
 student2
(2 行记录)

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查看库中某个表的结构:

使用SQL去查询:
SELECT a.attnum,
       a.attname AS field,
       t.typname AS type,
       a.attlen AS length,
       a.atttypmod AS lengthvar,
       a.attnotnull AS notnull,
       b.description AS comment
  FROM pg_class c,
       pg_attribute a
       LEFT OUTER JOIN pg_description b ON a.attrelid=b.objoid AND a.attnum = b.objsubid,
       pg_type t
 WHERE c.relname = 'student'
       and a.attnum > 0
       and a.attrelid = c.oid
       and a.atttypid = t.oid
 ORDER BY a.attnum

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使用命令查询
psql>\d tablename

yiibai_db-# \d student
                  数据表 "public.student"
   栏位   |      类型      | Collation | Nullable | Default
----------+----------------+-----------+----------+---------
 name     | character(100) |           |          |
 id       | integer        |           |          |
 subjects | character(1)   |           |          |

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显示数据的字符：\encoding

yiibai_db-# \encoding
GBK
yiibai_db-#