Slick VS ecto

Made a PR on slick to document this https://github.com/slick/slick/pull/2760 (workaround is quite easy, you can just define def tupled = (apply _).tupled in the companion object of the case class and it will also compile for all Scala versions).

The Scala ecosystem has a few ways to do composable type-safe query building, e.g. Slick[0] or more recently Quill[1]. . I believe both also have ways to do compile-time string interpolation (e.g. sql"""select * from users where id = ${user.id}""") which generate prepared statements (I know Slick does prepared statements. Quill has similar macros but I haven't looked into how safe they are to use).

[0] https://scala-slick.org/

Release notes at https://github.com/slick/slick/releases/tag/v3.5.0-M3

With all this in mind, I landed at the first candidate: slick from https://scala-slick.org/ that you all probably know.

I think Slick's current priority is also getting in Scala 3 support: https://github.com/slick/slick/issues/2177

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https://github.com/slick/slick/pull/2097 now I use slightly lower version of slick so this might be an upgrade that resolves (I do recall using it in 21 and it was still buggy and I filed a ticket, which I cannot find at the moment), but given a complex enough query (we have one in PROD which has tons of flexibility in terms of filters that can be passed in) but it also makes for complex code.

I started writing a reply but then I realized it would be long and depends on exactly what you mean, so maybe it's better to post the question in https://github.com/slick/slick/discussions/categories/questions?

I purchased the very entertaining book Seven Languages in Seven Weeks. Although I found Haskell fascinating and tempting, I knew it was unrealistic to introduce it in our company. Scala on the other hand looked like it could be the holy grail: All the characteristics I was looking for, no need to abandon the JVM and its cornucopia of tools and libraries, and the possibility for coexistence with Java and therefore incremental adoption. After implementing some simple programs to identify any immediate risks of committing to the language and its ecosystem, I started to introduce Scala in customer projects. Luckily, I was fortunate enough to work with open-minded, curious, and ambitious team members who were also experienced enough to appreciate the benefits of the language. We immediately applied our experience with functional programming, and embraced immutability. Libraries like Slick and Akka HTTP (we actually started out with its predecessor, Spray) made building database-backed REST services a breeze. And the resulting code was robust and highly maintainable. Scala's expressive type system and type inference made it easy to build a restrictive, consistent domain model without bloating the code. There was virtually no overhead. Any boilerplate could be easily abstracted out. In the end, the application code felt natural, concise and elegant. Programming was fun again.

To ruin the party, deterministic UUID generation is exactly what UUID v5 is designed for. And since Ecto does not validate UUIDs against their specs, you might as well use uuid again and do:

To me this looks a lot like ecto https://github.com/elixir-ecto/ecto

Is there a significant difference?

Ecto database driver use-case

When it comes to building microservices, Go has the advantage of being easier to deploy and tighter integration with gRPC. On the other hand, Elixir will provide a more expressive layer to communicate with the database through Ecto.

May I ask why CouchDB though? Is it for the offline support?

Phoenix comes with its own database tool called Ecto[0] which is excellent, and it uses Postgres by default. If you're not intended to leverage CouchDB for offline support you should go Postgres without a second thought.

That said, I'm also curious about how to implement offline support with Phoenix in a nice and trivial way.

[0] https://github.com/elixir-ecto/ecto

The best would be to set aside at least 40 minutes of study a day. Being 20 minutes focused on the core of the language, solving problems and a website that can help you a lot and exercism. Another 20 minutes some of the core frameworks like: Phoenix, Ecto, Enum

This is a testiment to the value and productivity of Phoenix, but the resulting code is just basic CRUD. The views are tied 1:1 with their database-backed Ecto schemas. One thing to note is that Phoenix generates DDD-style contexts. This is unlike Rails, which would produce a typical ActiveRecord sprawl: bloated models directly being accessed and lazily queried across the entire application.

Ecto uses prewalk to count the number of interpolations within a given expression.

I've used my share of data access libraries and patterns (e.g. hibernate, activerecord, ecto, ...). The only time I've been happy is when I use raw SQL for non-dynamic SQL and a lightweight query builder for everything else.

I feel like I always run into some thing that at best isn't intuitive to express/read and at worse, cannot be expressed. If I remember correctly, when I was learning Elixir/Ecto, https://github.com/elixir-ecto/ecto/issues/1616 issue and the lack of lateral join support caused me issues.

Want to create a user?

"insert into users (id, name, status) values ($1, $2, $3)"

Our query builder takes pretty raw SQL fragments:

    q = Query.new()