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Comment by tt | Hacker News Reader

> The idea of putting any logic in the database never did make much sense to me for these exact reasons.

I'm a big proponent of enforcing business rules right into the data model. Constraints such as not null, reference constraints, or even conditional unique constraints (yes, there's such a thing!) should be enabled wherever possible.

Just remember, your app will not be the final app that makes use of the data. Your app comes and goes, along with many other apps written by many others. But the data lives "forever."

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In my opinion the notion of implementing business logic outside of the database and acknowledging the longevity of the data are not necessarily in conflict. You need to have a well defined model and you can choose whether the database is a full implementation of that model or just a representation of the state of that model.

I don't find databases well suited for expressing complex behavior - programming languages are far better at that.

Business rules applied to the data are good (constraints, etc.) because they force the developer to fix the old data when they introduce a new rule. Doing data migration from old systems is quite painful when required fields aren't there. It's hard work to introduce a foreign key constraint when there are a million rows that have to be updated...

However, much of what people call business rules are much more complex logic than that. I like the store things like the state transition mappings in the database, but ultimately the application is the more flexible place to execute the state transitions.

> Just remember, your app will not be the final app that makes use of the data. Your app comes and goes, along with many other apps written by many others. But the data lives "forever."

Here here - that quote is so close to what Tom Kyte always says I reckon you are either Tom himself or an Oracle DB programmer :-)

data can't "live" very long locked in an airtight cage...

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