Question
Is it a good rule of thumb for database IDs to be "meaningless?" Conversely, are there significant benefits from having IDs structured in a way where they can be recognized at a glance? What are the pros and cons?
Background
I just had a debate with my coworkers about the consistency of the IDs in our database. We have a data-driven application that leverages spring so that we rarely ever have to change code. That means, if there's a problem, a data change is usually the solution.
My argument was that by making IDs consistent and readable, we save ourselves significant time and headaches, long term. Once the IDs are set, they don't have to change often and if done right, future changes won't be difficult. My coworkers position was that IDs should never matter. Encoding information into the ID violates DB design policies and keeping them orderly requires extra work that, "we don't have time for." I can't find anything online to support either position. So I'm turning to all the gurus here at SA!
Example
Imagine this simplified list of database records representing food in a grocery store, the first set represents data that has meaning encoded in the IDs, while the second does not:
ID's with meaning:
Type
1 Fruit
2 Veggie
Product
101 Apple
102 Banana
103 Orange
201 Lettuce
202 Onion
203 Carrot
Location
41 Aisle four top shelf
42 Aisle four bottom shelf
51 Aisle five top shelf
52 Aisle five bottom shelf
ProductLocation
10141 Apple on aisle four top shelf
10241 Banana on aisle four top shelf
//just by reading the ids, it's easy to recongnize that these are both Fruit on Aisle 4
ID's without meaning:
Type
1 Fruit
2 Veggie
Product
1 Apple
2 Banana
3 Orange
4 Lettuce
5 Onion
6 Carrot
Location
1 Aisle four top shelf
2 Aisle four bottom shelf
3 Aisle five top shelf
4 Aisle five bottom shelf
ProductLocation
1 Apple on aisle four top shelf
2 Banana on aisle four top shelf
//given the IDs, it's harder to see that these are both fruit on aisle 4
Summary
What are the pros and cons of keeping IDs readable and consistent? Which approach do you generally prefer and why? Is there an accepted industry best-practice?
