When developing a DW, the followings are “not to” things:
Starting with the wrong sponsorship chain
Setting expectations that you cannot meet and frustrating executives at the moment of truth
Engaging in politically naïve behavior
Loading the warehouse with information just because it is available
Believing that data warehousing database design is the same as transactional database design
Choosing a data warehouse manager who is technology oriented rather than user oriented.
Focusing on traditional internal record-oriented data and ignoring the value of external data and of text, images, and, perhaps, sound and video.
Delivering data with overlapping and confusing definitions.
Believing promises of performance, capacity, and scalability.
Believing that your problems are over when the data warehouse is up and running.
Focusing on ad hoc data mining and periodic reporting instead of alerts.