Abstract: The invention describes a method, a system and a computer program product for masking data in a database system. The database system includes a database in which sensitive data is stored. The database system also includes a Database Management System (DBMS) which manages the database. Further, the database system includes a plurality of users that run various database queries and commands on the sensitive data. Masking policies are set for users that have access to the sensitive data. Users without privileges to view or manipulate sensitive data may run their queries and commands on masked data, while users with privileges to run and manipulate sensitive data may run their queries and commands on sensitive data. The masked data is generated in real-time and is not stored on the database, thereby preserving its integrity.