Friday, September 23, 2011

SQL Server interview questions: - State the term SQL injection in SQL Server?

This is one of the most favorite SQL Server interview questions asked by the

It is basically a Form of attack on a database-driven Web site in which the
attacker executes unauthorized SQL commands by taking advantage of insecure code
on a system connected to the Internet, bypassing the firewall. SQL injection
attacks are used to steal information from a database from which the data would
normally not be available and/or to gain access to an organization’s host
computers through the computer that is hosting the database.

SQL injection attacks typically are easy to avoid by ensuring that a system has
strong input validation.

As name suggest we inject SQL which can be relatively dangerous for the
database. Example this is a simple SQL

SELECT email, passwd, login_id, full_name
FROM members
WHERE email = 'x'

Now somebody does not put “x” as the input but puts “x ; DROP TABLE members;”. So the actual SQL which will execute is:-

SELECT email, passwd, login_id, full_name
FROM members
WHERE email = ‘x’; DROP TABLE members;

Think what will happen to your database.

Also see another SQL server interview questions video on difference between unique key and
primary key as follows: -

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