Another important activity of the design phase is designing the data storage component of the system. This chapter describes the activities that are performed when developing the data storage design. First, the different ways in which data can be stored are described. Several important characteristics that should be considered when selecting the data storage format are discussed. The process of revising the logical data model into the physical data model is then outlined. Because one of the most popular data storage formats today is the relational database, optimization of relational databases from both storage and access perspectives is also included.