Watermarking relation al database is a technique which can provide ownership protection and temper proofing for relational databases. Although it has been developed over ten years, it is still not popular. For attracting more people to study this technique, we introduce it in detail in this paper. The main contributions of this paper include: 1) To the best of our knowledge, this is the first paper which specially surveys data distortion watermarking relational databases; 2) We define a new requirement analysis t able for data distortion watermarking relational databases and use it to analyze important and t he newest research of data distortion watermarking relational databases; 3) We explain background knowledge of watermarking relational databases, such as types of attacks, requirements, and basic techniques.
