pg学习_基本表定义_创建表

创建表的语法结构
highgo=# \h create table
Command:     CREATE TABLE
Description: define a new table
Syntax:
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] table_nam
e ( [
{ column_name data_type [ COLLATE collation ] [ column_constraint [ ... ] ]
| table_constraint
| LIKE source_table [ like_option ... ] }
[, ... ]
] )
[ INHERITS ( parent_table [, ... ] ) ]
[ WITH ( storage_parameter [= value] [, ... ] ) | WITH OIDS | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE tablespace_name ]

CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] table_nam
e
OF type_name [ (
{ column_name WITH OPTIONS [ column_constraint [ ... ] ]
| table_constraint }
[, ... ]
) ]
[ WITH ( storage_parameter [= value] [, ... ] ) | WITH OIDS | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE tablespace_name ]

where column_constraint is:

[ CONSTRAINT constraint_name ]
{ NOT NULL |
NULL |
CHECK ( expression ) [ NO INHERIT ] |
DEFAULT default_expr |
UNIQUE index_parameters |
PRIMARY KEY index_parameters |
REFERENCES reftable [ ( refcolumn ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
[ ON DELETE action ] [ ON UPDATE action ] }
[ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]

and table_constraint is:

[ CONSTRAINT constraint_name ]
{ CHECK ( expression ) [ NO INHERIT ] |
UNIQUE ( column_name [, ... ] ) index_parameters |
PRIMARY KEY ( column_name [, ... ] ) index_parameters |
EXCLUDE [ USING index_method ] ( exclude_element WITH operator [, ... ] ) index_parameters [
WHERE ( predicate ) ] |
FOREIGN KEY ( column_name [, ... ] ) REFERENCES reftable [ ( refcolumn [, ... ] ) ]
[ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE action ] [ ON UPDATE action ] }
[ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]

and like_option is:

{ INCLUDING | EXCLUDING } { DEFAULTS | CONSTRAINTS | INDEXES | STORAGE | COMMENTS | ALL }

index_parameters in UNIQUE, PRIMARY KEY, and EXCLUDE constraints are:

[ WITH ( storage_parameter [= value] [, ... ] ) ]
[ USING INDEX TABLESPACE tablespace_name ]

exclude_element in an EXCLUDE constraint is:

{ column_name | ( expression ) } [ opclass ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ]
Create table 向当前数据库中追加一个新的表，新表为执行本命令的用户所有。
一个表的字段数目不能超过 1600 个，每一个字段的大小 不能超过 8192 字节(大对象字段除外)，用户表不能与系统表同名。

创建表的简单示例
highgo=# create table man(id int,name varchar);
CREATE TABLE
highgo=# \d man
Table "public.man"
Column |       Type        | Modifiers
--------+-------------------+-----------
id     | integer           |
name   | character varying |

通过脚本创建表
[highgo@node1 ~]$ vi create_aman.sql
create table aman(id int,name varchar);
执行脚本
highgo=# \i /home/highgo/create_aman.sql
CREATE TABLE

显示表结构
highgo=# \d aman
Table "public.aman"
Column |       Type        | Modifiers
--------+-------------------+-----------
id     | integer           |
name   | character varying |

通过子查询生成表
只创建表结构
highgo=# create table bman
highgo-# as
highgo-# select * from aman where 1!=1;
SELECT 0
highgo=# select * from bman;
id | name
----+------
(0 rows)
创建表结构并复制所有的表记录
highgo=# create table cman
highgo-# as
highgo-# select * from aman;
SELECT 1
highgo=# select * from cman;
id | name
----+------
1 | aman
(1 row)