by Kevin S
It’s becoming clear that Entity-Relationship models can be just as complicated as Human-Relationships. Fortunately, the journal “Improving Database Design through the Analysis of Relationships” is here to shine some light on the subject. This journal quickly covers all of the basics and dives into a detailed study of relationships. They cover such sticky situations which are often not divulged deeply in textbooks such as high degree relationships, derived relationships, and several more. The four aspects they use as a guide to analyzing a relationship are as follows:
1. Cardinalities or mapping ratios.
2. The degree of a relationship.
3. The recursive nature of a relationship (i.e., an entity participating more than once in a relationship).
4. Interrelationship constraints.
Each of these rules can also be tied into several of the things we are covering in chapter 3. The authors use these guidelines and discuss generalization, specialization, and the overlapping/disjoint rules. Breaking down a relationship into 4 sections to better understand what is happening or what needs to happen is a great way to better create a solid relationship.
I like how this article is written, as it is easy enough for a novice to read and understand yet in depth enough for a seasoned professional to refer to. I did notice that some things such as the notations on the diagrams seem to be out of date, but then again it was written in 1999 so it may have actually been a pioneer to what we are used to seeing now. Overall this was a helpful and informative journal.
DEY, D., STOREY, V. C., & BARRON, M. B. (1999). Improving database design through the analysis of relationships. ACM Transactions on Database Systems, 24(4), 453-486. Retrieved from http://0-delivery.acm.org.opac.library.csupomona.edu/10.1145/340000/331984/p453-dey.pdf?ip=184.108.40.206&acc=ACTIVE SERVICE&CFID=174516808&CFTOKEN=20726611&__acm__=1350250254_b2e118a4dcd67cd7deb66fc47b46ef08