openGauss每日一练第15天-表管理3

1.创建表和约束

omm=# create table t1(id bigint,name varchar(50) not null,age int default 20,primary key(id));
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "t1_pkey" for table "t1"
CREATE TABLE

2.使用\d tableNmae命令查看表的定义、模式和所有者

omm=# \d t1
              Table "public.t1"
 Column |         Type          | Modifiers  
--------+-----------------------+------------
 id     | bigint                | not null
 name   | character varying(50) | not null
 age    | integer               | default 20
Indexes:
    "t1_pkey" PRIMARY KEY, btree (id) TABLESPACE pg_default

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 
------------
 t1
(1 row)

4.查看一个表下有哪些约束

omm=# select conname, connamespace, contype, conkey   from pg_constraint  where conrelid in (  select oid  from pg_class   where relname='t1');
 conname | connamespace | contype | conkey 
---------+--------------+---------+--------
 t1_pkey |         2200 | p       | {1}
(1 row)

5.查看一个表属于数据库的哪个模式

omm=# SELECT * FROM information_schema.tables WHERE table_name='t1';  
 table_catalog | table_schema | table_name | table_type | self_referencing_column_name | reference_generation | user_defined_type_catalog | user_defined_type_schema | u
ser_defined_type_name | is_insertable_into | is_typed | commit_action 
---------------+--------------+------------+------------+------------------------------+----------------------+---------------------------+--------------------------+--
----------------------+--------------------+----------+---------------
 omm           | public       | t1         | BASE TABLE |                              |                      |                           |                          |  
                      | YES                | NO       | 
(1 row)