Databases Reference
In-Depth Information
deal to wait a couple of days to meet with a key IT or business person, over
the life of the project this can add weeks to the schedule — just waiting
to have the opportunity to ask a question. Moreover, if the question
cannot be answered by that individual, then the process begins again to
gain access to the next person in the chain. It is much better to create
an environment where the data warehouse team is provided an open
door directly to anyone (within reason!). This requires that both business
and IT management communicate the importance of the data warehouse
project to everyone else. It also means that the data warehouse team must
act responsibly and respect everyone's time.
Experience level of the team:
There is a lot to learn when working on a
data warehouse project, especially for the first time. It takes some time to
learn data warehousing concepts and principles. It also takes some time
to learn and
become efficient
with using any new technology.
Lack of access to the right IT people:
Usually, several key people
have knowledge of how a system works. These IT people are in high
demand, and the data warehouse team may have trouble scheduling
time with them. These individuals often play a critical role in keeping
the operational system running and may be involved in other systems
development projects.
Each of these items can increase the amount of time needed to design and
build the ETL system. This is also the part of the project where you are likely
to have the largest number of resources all working on the project. A small
core group can gather requirements and develop the data model, but now
many more people can work at the same time to build the ETL system. Small
organizations may still have a small core team (likely the same core team),
whereas large enterprises may have a dozen or more people working on this.
All this work translates into dollars, for internal business and IT staff and
third-party consultants.
TIP
Use what you know about the organization to anticipate common project
impediments. Try to build time into the project schedule to deal with these. For
example, if the team is inexperienced, then include time and resources for
education and mentoring.
Balancing Requirements and Data Reality
Organizations often have great ideas about what they want to do and how they
would like to use data to help them. However, the data warehouse is limited by
the data that the organization actually has. The business requirements can be
