Question about foreign key?

Question

Table1

.............

name nvarchar(20)

rollnumber int primary key

Table2

-----------

empno int foreign key

Here I use different names "rollnumber" and "empno" for the two tables instead of giving rollnumber in the second table. How can I refer 'rollnumber' using the foreign key 'empno'?

Answer 1

First off, what database product are you using? Always include the OS, language, product, etc in your questions so you can get an accurate answer.

If I am not mistaken, you can define a foreign key using any column name you want - I don't really think that is an issue. It may be problematic in MS Access - that's why it's always good to include the name of the product you are working with.

Really, I think it boils down more to good practice. It could be confusing to have a column named one thing in one table, and another thing in another table. I would suggest standardizing your naming.

But as far as using a different column name, I don't think there are any restrictions in SQL.

EXAMPLE :

Foreign Key (Customer_SID) references CUSTOMER(SID));

In this example, the column is named 'Customer_SID' in one table, and just 'SID' in the other one.

Answer 2

what is it actually are u trying to do??.. is it programming??..

if not.. (if it's written)

if ur allowed to add another table then u can create fro example table 3.. then make empno as the foreign key and rollnumber as the public.. in that way you could be able to create such connections..