Comments/suggestions/PRs/etc. welcome

# arrow

[Bob Glamm]

Comments/suggestions/PRs/etc. welcome

[raulraja]

Looks great.

[raulraja]

I'd like to suggest that once we have arrow meta ready string interpolated queries are type checked and potentially compilable for verification against a schema

[raulraja]

So there is an extra layer of type safety in textual queries

[raulraja]

Additionally the row mapping operations can potentially be auto derived also when we have the arity support for meta

[raulraja]

Since you can go from data class to a tupled result which then is automatically mapped to the data class properties

[Bob Glamm]

Re: type-checked interpolated queries: I started to think about parameterized queries over the weekend a la Spring's NamedParameterJdbcTemplate, but I think the idea of type-checked queries is better still

[Bob Glamm]

Re: row-mapping, I'd like to be able to offer an automatic way to do the type conversion, since I think database row to data class constructor is likely to be a very common case

[raulraja]

I would like to also recommend to take a look at scalaz schema and skewmorph, if this grows into more features there needs to be a means for schema evolutions of some short

[Bob Glamm]

I'll take a look at both. I hadn't necessarily considered schema evolution as part of this yet because I usually defer those operations to something like Flyway

[Bob Glamm]

Also I figured I would start to look at https://tpolecat.github.io/doobie/ (Rob Norris' database FP lib for Scala + cats)

[raulraja]

Flyway is great but orgs may also choose canonical schema solutions to transform models across other domains beside persistence or db

[raulraja]

Doobie is awesome

[raulraja]

We use it a lot at 47

[Bob Glamm]

oh, model transformations for (e.g.) network serialization boundaries or data exchange layers?

[raulraja]

I hope db4k becomes the Doobie of Kotlin 😀

[raulraja]

Yes I ment those kinds of transformations but that can be a separate lib

[Bob Glamm]

That is a very nice sentiment, but I expect I have years of learning Scala/cats/doobie/etc. before even approaching that point

[raulraja]

We are porting those libs to Kotlin too in order to have something like Mu

[Bob Glamm]

sorry, I am unfamiliar with Mu

[Bob Glamm]

oh https://higherkindness.io/mu/

[raulraja]

Yep

[raulraja]

Making db4k similar to Doobie in features should not be hard with arrow in the upcoming year and we will be happy to help

[Bob Glamm]

I think my current path forward will likely be to add some sort of minimal named parameter query support while arrow-meta is under development just so I have something to show my colleagues here at work; concurrently, I will dig in to Doobie to learn how it works

[raulraja]

That sounds good

[raulraja]

Doobie works with a custom free Monad

[raulraja]

That resembles IO and extends it's operation with more db primitives

[raulraja]

https://github.com/tpolecat/skunk

[Bob Glamm]

We had discussed earlier about interoperability of isomorphic functional types between Cats / Arrow via arrow meta, I think? I don't know if it is possible but if the types can seamlessly interoperate then maybe db4k doesn't need to be finished and we can simply use doobie

[raulraja]

There are issues related to how types are exposed publicly

[raulraja]

Every scala call would need wrapping and some that are solely offered via implicits will need to be explicitly passed

[raulraja]

Not sure it would be a good user experience or less maintenance than having a pure Kotlin lib

[Bob Glamm]

My sense is that isomorphic type interoperability could drive one or more Ph.D theses

[raulraja]

An arrow db lib is something we would pursue in arrow non dependent of the scala runtime

[Bob Glamm]

^^ that is actually probably the biggest argument for db4k

[raulraja]

So DB4k if it's not scala based

[Bob Glamm]

also the issue of joint compilation between Scala/Kotlin is not solved, either, as far as I am aware

[raulraja]

Yeah, I'd love if this was pure Kotlin because we can introduce it in the ecosystem provided is built on top Fx

[raulraja]

And it fits nicely with the rest of arrow

[Bob Glamm]

++, I will keep working through it, then. I will proceed although my progress will likely be slow

[Bob Glamm]

My co-workers have yet to see the light 😄

[raulraja]

That's great, we'll be happy to help you wherever we can

[Bob Glamm]

Thanks, I really appreciate that. I expect walking through the custom free monad in Doobie will result in significant enlightenment for me