| Author: Anil Kumar Pandey 03 Nov 2009 | Member Level: Diamond | Rating:  Points: 2 |
hi,
there can be one primary key for a table, if you want to reference it for other table make it as Foreign key..
Thanks & Regards
Anil Kumar Pandey
|
| Author: atulpatel 03 Nov 2009 | Member Level: Gold | Rating: Points: 2 |
hi,
you can get definitions of the all the keys on following link
http://faq.programmerworld.net/database/faq-ms-sql-server.html
Thanks,
Atul
|
| Author: ABitSmart 03 Nov 2009 | Member Level: Diamond | Rating: Points: 2 |
A primary key with multiple columns is called a candidate key.
Kind regards,
ABitSmart
DNS Web-master, DNS MVM
My blog
Thoughts.exe
|
| Author: Shameer 03 Nov 2009 | Member Level: Silver | Rating: Points: 2 |
Primary Key:
The PRIMARY KEY constraint uniquely identifies each record in a database table.Primary keys must contain unique values.A primary key column cannot contain NULL values.Each table should have a primary key, and each table can have only one primary key
Foreign Key:
A FOREIGN KEY in one table points to a PRIMARY KEY in another table.
Union:
The UNION operator is used to combine the result-set of two or more SELECT statements.
|