The term data warehouse life-cycle is used to indicate the phases (and their relationships) a data warehouse system goes through between when it is conceived and when it is no longer available for use. Apart from the type of software, life cycles typically include the following phases: requirement analysis, design (including modeling), construction, testing, deployment, operation, maintenance, and retirement. On the other hand, different life cycles differ in the relevance and priority with which the phases are carried out, which can vary according to the implementation constraints (i.e., economic constraints, time constraints, etc.) and the software specificities and complexity. In particular, the specificities in the data warehouse life-cycle derive from the presence of the operational database that feeds the system and by the extent of this kind of system that must be considered in order to keep the cost and the complexity of the project under control. Although the design phase is only a step within the overall life cycle, the identification of a proper life-cycle model and the adoption of a correct design methodology are strictly related since each one influences the other.