Strengthening the ownership rights on outsourced relational database is very important in today's internet environment. Especially where sensitive and valuable content is to be outsourced. Let the authors take an example of university database, weather data, stock market data, power consumption consumer behavior data and medical and scientific data. Digital watermarking technique provides solution to the problem. Watermarking is the process in which an informal data is incorporated in original data to protect the owner's copyright over that content.