课程作业

1.创建表和约束

--表名：test
omm=# create table test(
name varchar(50) not null --列约束,
omm(# omm(# id bigint,
omm(# age  int default 20 --列约束,
omm(# primary key(id) --表约束
omm(#      );
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "test_pkey" for table "test"
CREATE TABLE

2.使用\d tableNmae命令查看表的定义、模式和所有者

--查看表定义
omm=#  \d+ test;
                             Table "public.test"
Column |         Type          | Modifiers  | Storage  | Stats target | 	Description 
--------+-----------------------+------------+----------+--------------+-------------
id     | bigint                | not null   | plain    |              | 
name   | character varying(50) | not null   | extended |              | 
age    | integer               | default 20 | plain    |              | 
Indexes:
"test_pkey" PRIMARY KEY, btree (id) TABLESPACE pg_default
Has OIDs: no
Options: orientation=row, compression=no
--查询表模式和所有者
omm=# \dt+ test;
                                List of relations
Schema | Name | Type  | Owner |  Size   |             Storage              | Description 
--------+------+-------+-------+---------+----------------------------------+-------------
 public | test | table | omm   | 0 bytes | {orientation=row,compression=no} | 
(1 row)

3.查看某个模式下有哪些表

omm=#   SELECT table_name FROM information_schema.tables WHERE 	table_schema='public';
table_name 
------------
test
(1 row)

4.查看一个表下有哪些约束

--查看约束名称、约束类型

--表下有哪些约束

5.查看一个表属于数据库的哪个模式