DW Wisdom (4)

The final part of this small series on data warehouse wisdom looks at the enterprise strands. Enterprise DW moves away from the tactical departmental “point solutions” and into something that fits with strategic aspirations of the enterprise. On the face of it having a single solution across the enterprise as distinct advantages:

there is a single, consistent model of enterprise data
there is less duplication of data across the enterprise
it is possible to construct a security model such that the right people see all of the data that allows them to their jobs but not the information that is too sensitive for their job role
the origins of all of the business data can be traced back to source

In fact these aims are so laudable that they have been hijacked by other IT disciplines such as master data management, risk and compliance management, and business process reengineering.

Having a monolithic enterprise DW would seem to be the ideal solution to the twin problems of duplicated silos of data throughout the organisation and having a single truth so that the whole organisation share a common knowledge. But is it?

Perhaps the best way to answer this is to think about what we are trying to achieve. Information technology is there to serve the business (and not the other way around as some old-school developers might think!) The business defines their objectives and our challenge is to meet them. Business intelligence used to be about reporting the past – sales last quarter may have been as recent as it got, but today people want to know what happened yesterday and in some sectors what happened just a few moments ago. Business intelligence used to be about giving results to skilled analysts, but today is just as much about getting key measures to the people that need them, instantly; and these people range from the CEO right down to people on the shop floor. Couple that to the realisation that many businesses run their enterprises on a whole raft of best of breed solutions (what is right for store space planning is not necessarily right for payroll) and technologies and we get to a view that we really should a design a model where the data warehouse is the repository for the company’s reference data (one truth, one place) and for historic factual data (both raw and summarised) and to access the various source systems for up-to-the-minute reporting of company performance. Ever borrowing from other technologies (such as modern backup techniques) data warehouses designers have developed ways to minimise the invasive effects of slow queries on transactional systems.

Users don’t really care where the data sits – as long as they know where it comes from, they trust its authenticity and they get their query results back quickly enough they are happy.