Project:M36 Relational Algebra Engine | Hacker News Reader

Project:M36 Relational Algebra Engine

github.com

38 pointsspariev5 comments

At a previous company I worked at, we built a relational algebra to do server side data jobs and manipulation on NoSql style data calls. It was surprisingly effective. I proposed it at first figuring "ah it's not SQL, the team won't like it " but it was quickly adopted and proved very valuable for a couple of years. That was despite the lack of flexible enough generics and before even the Java 8 lambdas. The biggest downside was younger devs who didn't have the experience to think in data first approaches (initially at least!). I kinda regretted not making more effort to train them how to utilize relational algebra and all the flexibility it brings, even in Java.

it'll be interesting to see if this project gains traction!

What are your thoughts about modeling polymorphism in the relational algebra?

If you are referring to object-oriented polymorphism, "Out of the Tarpit" comments directly on this AT http://shaffner.us/cs/papers/tarpit.pdf page 12, the conclusion being that OO suffers from unnecessary state complexity.

In addition, the glut of ORMs demonstrate the various approaches to solving the impedance mismatch between the relational algebra and object-oriented architecture with no clear winning strategy.

Instead, the proposal from the "Out of the Tarpit" paper is "functional relational programming" which fuses relational algebra operations and declarative functional programming.

I invite you to take a look at how Project:M36 handles these requirements at https://github.com/agentm/project-m36/blob/master/docs/reach...

I am referring to traits and variant types.

Primarily just that Java (7's) type system is categorically incapable of expressing more sophisticated types. You can get some basic type testing using abstract classes to define dataset column types. Java 8's type system might have some extra features to allow it to do this without significant boilerplate. E.g. To keep runtime generics in Java you can instantiate subclass instances which don't have type erasure.

The references solidsnack9000 mentions seem to be promising. I'll have to look into it! It seems like it'd apply to a system of using actors and data modeling I'm working on currently... Intriguing at least.

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