| Lesson 6 || Users of data |
| Objective || Explain the purpose of interviewing users of data. |
Interview Users of Data to generate Requirements Analysis is First Stage in Database Life Cycle
After you have completed your analysis of the existing business objects and rules, the next logical step in the process of Requirements Analysis is to interview those within the organization who use the data in the database.
Their collective insights into how data is used help in revising (for example, adding to or subtracting from) the list of business objects and rules collected earlier.
Users of data include an organizations employees and managers. There are three major reasons why users of data are interviewed by database designers:
- To determine how data are currently being used and perceived
- To determine whether users require additional information
- To determine future growth requirements
How an organization currently uses its data is determined not only by examining the existing database(s), but also by interviewing those who use the data. Stories on CD, Inc., for example, has a data-entry form to process customer
orders and a listing of its distributors in a Rolodex. Current informational needs of the company prescribe that distributors be considered a business object. Interviewing the current users of data:
1) Ted and 2) Lisa Martin in this case has uncovered this out of sight paper-based data sources.
Additional information needs
Rarely will an analysis of an organizations existing database--whether legacy or paper-based--reveal the full range of an organizations informational needs. If that were the case, the role of the database designer in creating a database would be greatly diminished.
Consider again the case of Stories on CD, Inc. Nowhere in their legacy database (supplemented with paper-based data entries) is there information to indicate that brochures are sent out three times per year to advertise their product.
However, Lisa revealed during an interview that she uses word-processing software to prepare descriptions of the CDs each time brochures are sent out. Knowing this, the designer can include a field in the CDs table to enter CD descriptions.
Lisa will now be able to query the database to extract that information for the brochures. This will be a great time-saver for the business.
Interviewing data users about future needs enables the designer to rethink design options. For example, if the interview of Ted and Lisa revealed that they intended to sell CDs outside of the U.S. in about 18 months, the designer might refrain from placing any field constraints on address-related fields that would preclude data entry about overseas customers.
Again, documentation of the interviews is extremely important. As questions arise while designing the logical schema, notes taken here are reviewed and can point the designer in the right direction if more user information is needed.
The next lesson examines the next step in the Requirements Analysis process: creating a data flow diagram.