DATABASE DEVELOPMENT LIFE CYCLE - Database Design and Development: An Essential Guide for IT Professionals - page 126

1. Introduction. State the overall scope and purpose of the project. Include broad
project justification. Provide an executive summary for each subsequent
section.
2. Requirements collection methods. Describe the methods used for collecting
requirements. List departments and business units interviewed. List docu-
ments studied and applications reviewed.
3. Interview summaries. Include summaries for all key interviews. If you used
JAD methodology, attach JAD documentation.
4. Data groups. Provide information requirements in the form of data groups
compiled in the previous consolidation step. Pay special attention to this
section as it forms the foundation for the design phase.
5. Future information requirements. Include the requirements gleaned from
those interviewed and inferred from the planning documents.
6. Other information requirements. In this section, put down other requirements
such as data volumes, remote locations, data access patterns, data conversion
needs, and business rules.
7. User expectations. Record all special expectations in terms of data timeliness,
data integrity, problems, and opportunities.
8. User review and sign-off. Describe the procedure used for getting the require-
ments reviewed and signed off on by the users. Also, indicate how users may
request changes to the requirements definition and how the changes would be
accepted for inclusion.
THE DESIGN PHASE
As noted above, the outcome of the requirements definition phase drives the design
phase and the subsequent phases. Very specifically, the design phase transforms
the requirements collected in the previous phase into a design for the proposed
database system. All the materials and information gathered in the requirements
definition phase are used to produce the design. The product of the design
phase generally takes the form of a design diagram together with descriptions and
explanations.
In the design phase, you find answers to questions such as, How is the data
required by the users to be organized and structured? How is the data going to be
stored in physical storage? What are the file layouts? What are the data structures?
When you produce the design for a database system, you do so at two levels—one
at the level of physical storage and the other at a higher level showing just the data
structures. As you know, this type of separation of the design provides data inde-
pendence. Changes at one level need not propagate into changes at the other level.
Later chapters deal with the design of a database system in more detail. Chap-
ters 5, 6, and 7 elaborate the topic of data modeling that is part of the design process.
Chapters 8, 9, and 10 deal with design specifically with regard to the relational
model, which is a major focus of this topic. Chapters 11 and 12 also relate to the
design phase. Therefore, at this stage, when we are discussing the entire database
development life cycle (DDLC), we will be fairly brief about the design phase.
Enough will be said later. So just try to note the general concepts of design here.