Parameterization involves using parameterized queries to separate SQL code from user input. This technique helps prevent SQL injection attacks by automatically escaping special characters.

SQL injection attacks can lead to unauthorized user access in a database. Attackers exploit vulnerabilities in input validation to inject malicious SQL code into an application's SQL statements, which can allow them to gain unauthorized access as regular users.

Transformation is the stage in ETL (Extract, Transform, Load) process where data is converted or modified according to business rules and requirements before loading it into the target system.