As a tool for storing and managing data, relational database is widely used in many information systems. It is very critical issue to protect the copyright of relational data. As an invention of information hiding the digital watermark techniques have been attracting more interests in both research and industrial fields. Today database watermarking becomes the research topic because of the increasing use of relational database systems. In order to make watermarking Information more intuitive and easier to identify and to give authorization to the database, watermarking is been proposed.