Database Reference
In-Depth Information
With this additional information, you can now revisit the database specification of
chapter 3 (Figures 3-4b, 3-13 and 3-14) and revise it accordingly (left as an exercise for you).
In so doing, please observe that while the ERD of Figure
5-2
is similar to that of Figure 3-4b,
they are not identical; they highlight different aspects of a manufacturing environment, with
various areas of overlap. By examining both figures, you should come away with a better
sense of what a database model and specification for such an environment would likely entail.
The key is to apply sound information gathering techniques (as learned in your software
engineering course and summarized in appendix 3), coupled with your database knowledge.
5.6 The UML Model
An alternate methodology for database modeling is the
Unified Modeling Language
(UML)
notation. UML was developed by three contemporary software engineering paragons —
Grady Booch, James Rumbaugh and Ivar Jacobson. These three professionals founded
Rational Software during the 1990s, and among several other outstanding achievements,
developed UML for the expressed purpose of being a universal modeling language. Although
UML was developed, primarily for
object-oriented software engineering
(OOSE), it is quite
suitable for database modeling. Figure
5-9
provides a description of the main symbols
used in UML. Note that with UML comes a slight change in the database jargon (“entity” is
replaced with “object type”), consistent with the fact that UML is primarily for OOSE.
Figure 5-9.
Symbols Used in UML Notation for Database Modeling
