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(genuine question) What are the best alternatives to triggers? And what makes them a bad idea?

I'm pretty much with you on stored procedures.

I am sure there are good use cases for triggers but I have seen quite a few databases that used triggers a lot and it almost always felt like the equivalent of spaghetti code. Things are happening and it takes forever to figure out why they are happening.

Depends on your perspective. Yes, if you are an application developer with weaker skills to access the data integrity logic in the database. No, if are a skilled database guy with weaker knowledge of all the source code of all the applications (could be multiple) sharing the database. Things are happening and it takes forever pouring thru each app's code to find its data integrity logic to figure out why they are happening.

By centralizing data integrity logic in the database, you know where to look and that all apps using the database will abide by it.

I agree with you but in the cases I saw I felt that the triggers were used to fix problems in the code more than being part of a consistent data strategy. I admire well designed databases but unfortunately there aren’t too many of them out there.

I think part of the problem is that there is still this huge chasm between good coding skills and good database skills. It’s hard to have both.

Triggers definitely have their place and can be very useful. But they can pretty quickly grow out of control leading to lots of side effects making it difficult to maintain and possibly leading to performance issues. I think twice before adding a trigger to consider if it is really necessary because using triggers as your first tool to solve problems can lead to a lot of complexity.

I like the author's point about this:

> The trigger function itself was also written in the “schema.sql” file which meant that everything was clear and documented along with the other relevant schema information, thus easier to track and manage.

In my experience, in most cases the application doing the insert/update/delete is the best place to handle most side effects. That may be an on-demand API, a scheduled/queued job, etc. I've found triggers to be helpful and simple for audit and history tracking. There are definitely plenty of cases where triggers are useful and it probably depends a lot on your architecture.

We're talking about "data scientists" for whom software development is not their primary focus. Since SPs and triggers do not share SQL's advantage of being declarative; they are instead imperative, and non-developers should spend as little time as possible within imperative domains.

I'm not as anti-trigger as I am SP. Though I stay away from triggers in any case as the rest of the world is fairly negative on them.

For which usecase(s)? Triggers seem to be used for many different things...

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