Tuesday, March 20, 2012

Problem with foreign key

Hello,
I have a problem with foreign key. What I want to do is , have one foreign key referencing in two different tables! I have created three tables:

create table University(
UniversityID int not null,
Name nvarchar(50),
....
....
....
primary key(UniversityID )
);

create table Person(
PersonID int not null,
Name nvarchar(50),
....
....
....
primary key(PersonID )
);

create table Borrower(
BorrowerID int not null,
Name nvarchar(50),
MemberName int,
....
....
....
primary key(BorrowerID )
foreign key(MemberName) reference University,
foreign key(MemberName) reference Person,

);

So I want to have one column (in my example MemeberName) which referencing in two different tables. How can I do that??I am not entirely sure what you are trying to accomplish, could you please reword you question a little?|||

Quote:

Originally Posted by Motoma

I am not entirely sure what you are trying to accomplish, could you please reword you question a little?


Ok, Sorry for that. Well, I have created three tables University, Person and Borrower. What I want to do is to have one column in table Borrower (lets say with name MemberId) which will be foreign key referencing together in the other two tables.
For example I gave the below syntax in SQL Server but it does not work:

create table Borrower(
BorrowerID ..........,
................,
..................,
...................,

foreign key (MemberID) references University,
foreign key (MemberID) references Person

);|||So you want the key to exist in either one of the tables? I'm not quite sure of the interaction you are looking for.|||

Quote:

Originally Posted by Motoma

So you want the key to exist in either one of the tables? I'm not quite sure of the interaction you are looking for.


ok I see. I will try to find another way. thanks

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