Top down approach
Single, central storage of data with centralized rules and control. Top down approach takes long time to build, high risk of failure. As they are not driven by end-users needs, there may be information needs gap.
Bottom Up approach
Faster and easier implementation of manageable pieces of information. Inherently incremental and important data marts can be scheduled first as per end user requirements. Facilitate project team to learn and grow. Each data mart has narrow scope, data redundancy and inconsistency may be present.
The best approach
Best approach is the basic understanding of information needs of an organization. That must include both present and long-term information requirements. In view of that a careful implementation and monitoring is critical.
[...] data s and different instructions for data presentation. For this reason, at the beginning of this bottom-process, it is strongly recommended that you make a single view of all data that will be valid at the [...]