如何在数据库中使用多个主键 [英] how to use multiple primary key in a database

问题描述

我正在使用c#.Net和Sql Server进行桌面应用程序.我采用了一种形式，其中有4个标签潜在客户ID，客户ID，客户名称和服务，并且它们是数据库的字段. ID和客户ID都不应有重复的值.因此，请告诉我该解决方案

我创建了两个表，一个表具有一个主键和两列

I am making desktop appication using c#.Net and Sql Server.I have taken a form in which there are 4 labels prospect id ,customer id,customer name and services and same are the fields of database.Nw i want that prospect id and customer id both should not have duplicate values.so please tell me the solution for this

I have created two tables one table having one primary key with two columns

create table PSM.dbo.conversion(Prospect_ID int,Customer_ID int ,Customer_Name varchar(50),Customer_Products_Services varchar(50),constraint pk1 primary key(Prospect_ID ,Customer_ID  ));

它成功运行


第二张表仅作为一列的外键

it run successfully


2nd table as foreign key of one column only

create table PSM.dbo.Customer_follow_up(Customer_ID int references conversion(Customer_ID),Customer_Name varchar(50),Customer_Products_Services varchar(50),Feedback nvarchar(1000));

在这里，得到一个错误


1776消息，级别16，状态0，第1行
在引用的表"PSM.dbo.conversion"中没有与外键"FK__Customer___Custo__5AEE82B9"中的引用列列表匹配的主键或候选键.
消息1750，级别16，状态0，第1行
无法创建约束.请参阅先前的错误.




问候

here,getting an error


Msg 1776, Level 16, State 0, Line 1
There are no primary or candidate keys in the referenced table ''PSM.dbo.conversion'' that match the referencing column list in the foreign key ''FK__Customer___Custo__5AEE82B9''.
Msg 1750, Level 16, State 0, Line 1
Could not create constraint. See previous errors.




regards

推荐答案

您只能有一个唯一键 [

You can have only one Primary Key[^] in a table.

But you can have multiple Unique Key[^].

首先，您不能创建多个主键，可以在多个列上创建单个主键.

First of all you can not create multiple primary key, you can create single primary key on more than one column.

CREATE TABLE dbo.test
(
test1 int,
test2 int,
test3 int,
CONSTRAINT somename PRIMARY KEY (test1 , test2 )

)

尝试此链接

复合键 [

try this Link

Composite Key[^]

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