This chapter introduces different alternatives to store and manage jointly relational and eXtensible Markup Language (XML) data sources. Nowadays, businesses are transformed in e-business and have to manage large data volumes and from heterogeneous sources. To manage large amounts of information, Database Management Systems (DBMS) continue to be one of the most used tools, and the most extended model is the relational one. On the other side, XML has reached the de facto standard to present and exchange information between businesses on the Web. Therefore, it could be necessary to use tools as mediators to integrate these two different data to a common format like XML, since it is the main data format on the Web. First, a classification of the main tools and systems where this problem is handled is made, with their advantages and disadvantages. The objective will be to propose a new system to solve the integration business information problem.