使用INHERITS创建的新表会继承一个或多个父表，子表只会继承父表的表结构和NOT NULL，DEFAULT，CHECK三种约束，主键，外键和唯一键以及索引不会被继承，所以修改父表的结构（增删字段），NOT NULL，DEFAULT和CHECK约束会自动同步子表修改。
示例1.
create table tbl_inherits_parent( a int not null, b varchar(32) not null default 'Got u', c int check (c > 0), d date not null ); test=# alter table tbl_inherits_parent add constraint pk_tbl_inherits_parent_a primary key(a); ALTER TABLE test=# alter table tbl_inherits_parent add constraint uk_tbl_inherits_parent_b_d unique (b,d); ALTER TABLE test=# create table tbl_inherits_partition() inherits (tbl_inherits_parent); CREATE TABLE test=# /d tbl_inherits_partition Table "public.tbl_inherits_partition" Column | Type | Modifiers --------+-----------------------+--------------------------------------------- a | integer | not null b | character varying(32) | not null default 'Got u'::character varying c | integer | d | date | not null Check constraints: "tbl_inherits_parent_c_check" CHECK (c > 0) Inherits: tbl_inherits_parent
示例2.
test=# alter table tbl_inherits_parent add column e int not null default 0; ALTER TABLE test=# alter table tbl_inherits_parent alter column b set default 'try me'; ALTER TABLE test=# /d tbl_inherits_partition Table "public.tbl_inherits_partition" Column | Type | Modifiers --------+-----------------------+---------------------------------------------- a | integer | not null b | character varying(32) | not null default 'try me'::character varying c | integer | d | date | not null e | integer | not null default 0 Check constraints: "tbl_inherits_parent_c_check" CHECK (c > 0) Inherits: tbl_inherits_parent
示例3.
除继承父表之外，创建子表时可以增加自己的字段
test=# create table tbl_inherits_partition1(f int) inherits (tbl_inherits_parent); CREATE TABLE test=# /d tbl_inherits_partition1 Table "public.tbl_inherits_partition1" Column | Type | Modifiers --------+-----------------------+---------------------------------------------- a | integer | not null b | character varying(32) | not null default 'try me'::character varying c | integer | d | date | not null e | integer | not null default 0 f | integer | Check constraints: "tbl_inherits_parent_c_check" CHECK (c > 0) Inherits: tbl_inherits_parent
示例4.解除继承
test=# alter table tbl_inherits_partition1 no inherit tbl_inherits_parent; ALTER TABLE test=# /d tbl_inherits_partition1 Table "public.tbl_inherits_partition1" Column | Type | Modifiers --------+-----------------------+---------------------------------------------- a | integer | not null b | character varying(32) | not null default 'try me'::character varying c | integer | d | date | not null e | integer | not null default 0 f | integer | Check constraints: "tbl_inherits_parent_c_check" CHECK (c > 0)
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