In recent times, the world has become highly dependent on computer science which has become extends to various vital and secondary areas of life, such as social communication, security, commerce, marketing, training, and other fields, as many institutions have become dealing with a huge amount of information to Storage and use for their benefit, in order to manage the present and the future well. This situation made many institutions need several means to keep pace with this great development of information in terms of quantity and quality, without losing what they could possess of previous information stored within databases, often relational system which provide easy ways of dealing with the information, also provides the possibility of applying several complex and important calculations and elicit. Developers in recent days have came out with what's called a NoSQL database, that surpasses its previous predecessor, these developers have also made many programs and tools that works with this new structure, that's characterized in 4 different categories, each one differs from the other in its fundamentals, that's why finding a way to migrate Data Base with all of data and effects from a relational system to this new structure became a must. In this paper, we will study in-depth and comprehensively the different categories of the NoSQL system, by following the comparative approach using WSM method and depending on a set of characteristics and features, in order to determine the optimal category that enables us to completely migrate all data from a relational system with all its details, and capabilities towards a NoSQL system, in order to put the first step to start studying the migration of data from a relational system to a NoSQL system