oracle中 怎么設(shè)主外鍵?

以oracle自帶的用戶scott為例。

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create?table?dept(

deptno?number(2)?primary?key,?--deptno?為?dept表的主鍵

dname?varchar2(10),

loc?varchar2(9)

);

create?table?emp(

empno?number(4)?primary?key,?--empno?為?emp表的主鍵

ename?varchar2(10),

job?varchar2(9),

mgr?number(4),

hiredate?date,

sal?number(7,2),

comm?number(7,2),

deptno?number(2)?references?dept(deptno)?--dept表中deptno字段?為?emp表的外鍵

);

oracle創(chuàng)建外鍵

create TABLE zhao(

id number primary key,

mingcheng nvarchar2(50),

neirong nvarchar2(50),

jiezhiriqi date,

zhuangtai nvarchar2(50)

);

create TABLE tou(

id number primary key,

zhao_id number,

toubiaoqiye nvarchar2(50),

biaoshuneirong nvarchar2(50),

toubiaoriqi date,

baojia number,

zhuangtai nvarchar2(50),

foreign KEY(zhao_id) REFERENCES zhao(id)

);

foreign key (zhao_id) references to zhao(id)

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oracle怎么創(chuàng)建外鍵？

create TABLE zhao(\x0d\x0a id number primary key,\x0d\x0a mingcheng nvarchar2(50),\x0d\x0a neirong nvarchar2(50),\x0d\x0a jiezhiriqi date,\x0d\x0a zhuangtai nvarchar2(50)\x0d\x0a);\x0d\x0acreate TABLE tou(\x0d\x0a id number primary key,\x0d\x0a zhao_id number,\x0d\x0a toubiaoqiye nvarchar2(50),\x0d\x0a biaoshuneirong nvarchar2(50),\x0d\x0a toubiaoriqi date,\x0d\x0a baojia number,\x0d\x0a zhuangtai nvarchar2(50),\x0d\x0a foreign KEY(zhao_id) REFERENCES zhao(id)\x0d\x0a);\x0d\x0aforeign key (zhao_id) references to zhao(id)\x0d\x0a多了個(gè)to

oracle 定義表外鍵

-- 創(chuàng)建測試主表. ID 是主鍵.

CREATE TABLE test_main (

id INT,

value VARCHAR(10),

PRIMARY KEY(id)

);

-- 創(chuàng)建測試子表.

CREATE TABLE test_sub (

id INT,

main_id INT,

value VARCHAR(10),

PRIMARY KEY(id)

);

-- 創(chuàng)建外鍵

ALTER TABLE test_sub ADD CONSTRAINT main_id_cons FOREIGN KEY (main_id) REFERENCES test_main;