Supertype-Subtype Relationships In Tables

Deborah Melkin explains the supertype-subtype pattern in relational database architecture:

You don’t see a supertype-subtype relationship defined as such when you’re looking at the physical database. You’ll only see it explicitly in the logical data model. So what is the pattern and how do you know that you have one in your database?

This relationship exists where you have one entity that could have different attributes based on a discriminator type. One example is a person. Depending on the role of that person in relationship to the business, you will need to store different pieces of information for them. You need different information about a client than you do an employee. But you’re dealing with a person so there is shared information.

It’s a good pattern for minimizing data repetition.

Related Posts

Rant: NoSQL Isn’t A Thing

Grant Fritchey is in rare form today: Go and search through it for a NoSQL data management system. I’ll wait. You found one that was named NoSQL didn’t you. Oracle NoSQL, because Oracle. Of course. However, under the Database Model what did it say? Document Store. Why? BECAUSE NOSQL IS NOT A DATA STORAGE ENGINE! […]

Read More

In Defense Of The Layered Architecture

Sylvia Fronczak defends the layered architecture approach to software development: There are disadvantages to the layered architecture approach. And some aspects of it have been deemed not architecturally pure for domain-driven design. However, there are disadvantages to most approaches. The key is to understand both the advantages and disadvantages. Pick what architectural patterns work best […]

Read More

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Categories

August 2018
MTWTFSS
« Jul  
 12345
6789101112
13141516171819
20212223242526
2728293031