A recommended method for the development of data warehouse systems is to implement the warehouse in an incremental and evolutionary manner, as shown in fig. 2.15. First, a high-level corporate data model is defined within a reasonably short period that provides a corporate-wide, consistent, integrated view of data among different subjects and potential usages. This high-level model, although it will need to be refined in the further development of enterprise data warehouses and departmental data marts, will greatly reduce future integration problems.
Second, independent” data marts can be implemented in parallel with the enterprise warehouse based on the same corporate data model set as above. Third, distributed data marts can be constructed to integrate different data marts via hub servers. .Finally, a multitier data warehouse is constructed where the enterprise warehouse is the sole custodian of all warehouse data, which is then distributed to the various dependent data marts.
Fig. 2.15. A Recommended Approach for Data Ware/rouse Development