SQL Server Interview Questions

Lets try to prepare list of possible interview questions on "Constraints". I will answer all of these in next section.

1) What is a Primary Key?
2) What is Unique Key?
3) What is the difference between Primary Key and Unique Key?
4) What is Check Constraint?
5) What is RULE?
6) What is the difference between RULE and Check Constraint?
7) How to create a relationship between two tables?
8) Can we create a Foreign Key with out Primary Key?
9) What is the table name,that contains the Primary Key, Unique Key and Foreign Key Information?
10) What is the table name, that contains Check Constraint Definition?
11) What is the table name, that contains RULE Constraint definition?
12) Can we have RULE and Check Constraint on the same column?
13) Can we apply Integrity Constraints on Computed Columns?
14) Can you write a query to find out the Child Table Name and Parent Table Name and the Columns to join?
15) Can you drop a Parent Table with out affecting its child tables?
16) How to disable and Enable the constraints?
17) What is the order of Constraints execution?


Do you think of anything else on "Constraints"?? If yes then Please post it in Comments section.