[zozbot234]

Views can perform arbitrary queries. They can achieve any kind of inference starting from the base data that's stored in tables. (Keep in mind that modern SQL is fully Turing-complete.) This makes any view-augmented database a viable source of rich, complex knowledge, not just mere information.

[kroolik]

But I doubt unleashing the full expressive power of SQL is the point here. It would easily turn a moderately complicated "remove column" migration a real maintenance hell.

In the simplest form, when you add a column to some schema, it should be materialized in the base schema and exposed via the migration view.

The problems start when you add and remove 20 columns because even though they are no longer visible in migration schemas, they take up space in the base schema

[kroolik]

@lallysingh, sorry, can't reply directly.

All I'm saying is that I don't think we need a full Turing-complete cannonball to hit the (relatively) small fly of no-downtime migrations.

Is it a silver-bullet? It's Turing-complete so high chances yes. But for me it has a high risk of causing a silver-poisoning.

Personally, I would stick with simpler solutions.

[squiggleblaz]

Butting in to say: Maximum reply depth is relative to the view. Just click on the comment's time and you will get a form with a reply field.

[moreira]

WOAH! I’ve been using HN for years and had NEVER realised that. And I honestly keep seeing people saying they can’t reply, either. This changes things!

[Sr_developer]

Let's see how deep this rabbit-hole goes

[fabianlindfors]

Yes, this approach might actually decrease the power of your database as some things become much trickier. It might be worth trading of some expressive power of the database for smoother, less hands-on migrations though, which is what I'm going for.

[lallysingh]

That sounds like problems upstream of this technique. Are you complaining that it isn't a silver bullet or that it's so powerful that it'll be abused?