Sql中的主键和外键 [英] Primary Key and Foreign Key in Sql

问题描述

如何在SQl中使用主键和外键?.给出示例解决方案???

问候
Balamurugasn

Hi,
How to use Primary Key and Foreign Key in SQl?.Give Solution with Example???

Regards
Balamurugasn

推荐答案

Google是您的朋友:很好，经常拜访他.与在这里发布问题相比，他可以更快地回答问题.

使用您的问题作为搜索词进行的快速搜索带来了150万次匹配: http://www.w3schools.com/sql/sql_foreignkey.asp [ ^ ]并提供了很好的解释和示例.

将来，请尝试至少自己进行基础研究，不要浪费您或我们的时间.

Google is your friend: Be nice and visit him often. He can answer questions a lot more quickly than posting them here...

A very quick search using your question as the search term gave over 1.5 million hits: Google : How to use Primary Key and Foreign Key in SQl[^]
The first hit is W3Schools: http://www.w3schools.com/sql/sql_foreignkey.asp[^] with a good explanation and example.

In future, please try to do at least basic research yourself, and not waste your time or ours.

假设有两个表

创建表empmaster
(
Empid Int identity(1,1)主键，
姓varchar(20)，
Empaddress varchar(50)，
EMpDoB日期时间
)

创建表empjob
(
jobid int不为null，
empid int不为null，
jobdesc varchar(40)，
外键(empid)参考empmaster(empid)
)

在这里，我们指的是主键和外键关系，以获取具有jobdesc的特定员工的详细记录.
希望它能对您有所帮助.

Assume there are two tables

Create table empmaster
(
empid Int identity(1,1) primary key,
Empname varchar (20),
Empaddress varchar(50),
EMpDoB datetime
)

create table empjob
(
jobid int not null,
empid int not null,
jobdesc varchar(40),
FOREIGN KEY (empid) REFERENCES empmaster(empid)
)

here we are refering the primary key and foreign key relationship to get the detail records for particular employee with jobdesc.
Hope its help you.

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