Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. An SQL injection is often used to attack the security of a website by inputting SQL statements in a web form to get a badly designed website to perform operations on the database other than the usual operations as intended by the designer. SQL injection is a code injection technique that exploits a security vulnerability in a website's software. The vulnerability happens when user input is either incorrectly filtered for string literal escape characters embedded in SQL statements or user input is not strongly typed and unexpectedly executed.