Gadgets and Technology

The next step in the process is where we configure an ad hoc query tool to operate against the data warehouse. These end-user access tools are capable of automatically generating the database query that answers any question posed by the user. The users will typically pose questions in terms that they are familiar with (for example, sales by store last week); this is converted into the database query by the access tool, which is aware of the structure of information within the data warehouse.

The process of generating a database query may sound simple enough, but in .practice can be very tricky to get right. The challenge is not to get the user access tool to generate the query; rather, it is to cajole the tool into generating a performant query. Our experience has been that this process is time consuming, and can result in substantial changes to the database in order to force the tool to generate the optimum query. To this end, we can mitigate project risk by performing this activity within a separate phase, after the first benefits are delivered. We do not mean to imply that you should never perform this activity within one of the other phases. It is our opinion that project risk and complexity will substantially increase, if the user access tool is configured and tuned at the same time that the database is being substantially modified.