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Entity-Relationship Variability
There comes a time1 every semester where I feel like I’ve entered the Thunderdome. I hear cheering and shouting, the smell of swine is strong, Tina Turner is announcing. My opponent is myself, and I can look pretty mean sometimes.
I’ve gone up against myself like this many times before; I know what kind of fight it means. Drawn out and ugly. And sure enough, I’m drawn out and ugly.
Since I usually have to work things out by talking about them, I’m going to try and articulate this homework problem that followed me into sleep and back. It has to do with entity relationship data modeling.
You’re shown a traffic citation correction notice2 and told there are 5 entities represented by it. You’re asked to break the traffic citation correction notice into “things” that can be “identified” then explain the nature of relationships between them3. How will the numbers of one thing compare to the number of a related thing? Does one thing have to exist for the other, related thing to exist?
Really? Just 5 entities? Is one of them the thing itself, the traffic citation correction notice? I’m having a hard time accepting that there are only 5.
If I were designing a data model to be used for law enforcement purposes across many states, I’d be more particular about how it was engineered. The relationships that appear between things could help solve crimes, save lives, and provide court systems with history and facts.
I’ve been pondering this for a couple days now. While I was writing this I did a fresh sketch of a data model that places no limitations on the number of entities involved.
What has me drawing it out is the fact that the more I think about it and reason through variations of the relationships between things, I find more variations. There are arguments to support good and bad design decisions and my mind gets stuck in this infinite loop of puzzling.
And my dreams are a drawn out puzzle where I’m shifting, turning and twisting pieces, looking for that fit.
But it’s due on Thursday. Should I settle on something with 5 entities? It doesn’t feel right. And I have to go to work now.
------------------------------------------------------------------------ …sometimes many times [↩]
- Seen above [↩]
- And I’m hoping we’re only talking about binary relationships. [↩]