Comment by onion2k | Hacker News Reader

Comment by onion2k | Hacker News Reader

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the code is not reusable accross different storage layers. So not portable.

In my 23-and-a-bit years of web development I've literally never changed the database engine on a project. Maybe that happens on other people's projects, but it's not something I consider important or even useful really. The notion that you can swap out your database for a different one without changing the application code to take advantage of the db you're moving to is ludicrous. Of course your database code isn't portable.

Websites that used MySQL and Myisam tables with raw SQL statements written as strings in PHP for the first decade of the web is one of the reasons why so many web developers still don't use things like transactions, stored procedures, views, etc. That's a bit of a tragedy. The web would be much better today if everyone had been using Postgres's features from the beginning.

If you write a project, you probably won't change the database. But you may add new data layer services such as a cache backend, a search engine with, a secret server, a session store, a permission micro service, etc. They will all interact with permissions and change where you source the data from.

Then there is the case where you don't write a project, but a lib. Or the case where you extract such a lib from a project. In that case, you limit the use case of your lib to your database. Because if you don't change database during your project life time, the users of your lib may start a new project with a different database.

This is why Django ORM allowed such a vibrant ecosystem: not because it allows changing the data base of one project (although it's nice to have and I used it several times), but also because it allow so called "django pluggable apps" to be database independant.

I have never seen anybody migrate out of PostgreSQL, but I HAVE seen people migrate out of Oracle, and DB2 because they are so expensive its worth the cost to migrate.

  I've literally never changed the database engine on a project

And some of us do it several times a day because we deploy to prod with Postgres but run testing and CI with SQLite.

Me too, until I found how fast Postgres is starting in Docker and for different languages there are now libraries helping you writing tests using Docker containers.

Well, you're doing it wrong. It's easy and fast to run tests against real postgres (takes a fraction of a second to spin up the DB for your tests if you do it right).

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