MapDB VS JDBI

I decided to start with an overview of what open-source options are currently available. When it comes to the implementation of the on-heap cache mechanism, the options are numerous – there is well known: guava, ehcache, caffeine and many other solutions. However, when I began researching cache mechanisms offering the possibility of storing data outside GC control, I found out that there are very few solutions left. Out of the popular ones, only Terracotta is supported. It seems that this is a very niche solution and we do not have many options to choose from. In terms of less-known projects, I came across Chronicle-Map, MapDB and OHC. I chose the last one because it was created as part of the Cassandra project, which I had some experience with and was curious about how this component worked:

So, it's an object database, like Zope's ZODB on Python?

I like the idea, but I'd like to learn about use cases for it.

Otherwise, in Java, MapDB is about as far as I'd be willing to go: https://github.com/jankotek/mapdb/

Anyway, without further ado, I found MapDB (https://github.com/jankotek/mapdb) which does exactly that. Of course, they also provide their own Java collection implementations as well, so I suspect using it with Vavr would be a poor idea, but it is very cool in its own right anyway. Of course, there is also Apache Derby and HSQLDB, and those great options with a long history as well. I haven't played with these in a while though, so I might give them a try again soon for some personal stuff.

In Java I like

https://mapdb.org/

It is more feature rich than you want but in Python I'd probably just use sqlite3 since it is in the standard library.

I have had good results with mapdb

While this may work for greenfield applications, I don't see this working well for preexisting schemas. From their getting started page: "Database fields are automatically created for any abstract getter methods", which definitely scares me away since they seem to be relying on automatic field type conversions.

I prefer to manage my schemas when I can and do type and DAO conversions via mapper classes in the very simple and elegant JDBI framework where you write SQL annotations above your DAO methods https://jdbi.org/#_declarative_api

JDBI does wonders for wonky old schemas you've inherited, since joins etc work out of the box (just throw them in your annotations!) The annotations can also link to .SQL files for the big hairy queries.

All these "do magic" frameworks (hibernate being one of the first) work in the simple cases but then fall apart whenever you need to do anything complex/not-prescribed. I end up having to dig into the internals of the framework to see what's going wrong which negates their whole value add.

> I've been doing ORM on Java since Hibernate was new, and it has always sucked.

Have you ever looked at something like myBatis? In particular, the XML mappers: https://mybatis.org/mybatis-3/dynamic-sql.html

Looking back, I actually quite liked it - you had conditionals and ability to build queries dynamically (including snippets, doing loops etc.), while still writing mostly SQL with a bit of XML DSL around it, which didn't suck as much as one might imagine. The only problem was that there was still writing some boilerplate, which I wasn't the biggest fan of.

Hibernate always felt like walking across a bridge that might collapse at any moment (one eager fetch away from killing the performance, or having some obscure issue related to the entity mappings), however I liked tooling that let you point towards your database and get a local set of entities mapped automatically, even though codegen also used to have some issues occasionally (e.g. date types).

That said, there's also projects like jOOQ which had a more code centric approach, although I recall it being slightly awkward to use in practice: https://www.jooq.org/ (and the autocomplete killed the performance in some IDEs because of all the possible method signatures)

More recently, when working on a Java project, I opted for JDBI3, which felt reasonably close to what you're describing, at the expense of not being able to build dynamic queries as easily, as it was with myBatis: https://jdbi.org/

That said, with the multi-line string support we have in Java now, it was rather pleasant regardless: https://blog.kronis.dev/tutorials/2-4-pidgeot-a-system-for-m...

I don't think there's a silver bullet out there, everything from lightweight ORMs, to heavy ORMs like Hibernate, or even writing pure SQL has drawbacks. You just have to make the tradeoffs that will see you being successful in your particular project.

I found JDBi[1] to be a really nice balance between ORM and raw SQL. It gives me the flexibility I need but takes care of a lot of the boilerplate. It's almost like a third category.

1. http://jdbi.org

You could use something like jdbi or mybatis. It's not as ugly as raw jdbc and easier to use without all of the gunk from an ORM like hibernate.

We use JDBI. Very simple and lightweight. It uses an object mapper not a full fledged ORM.

Alternatively there are... hybrid solutions like Kotlin's https://github.com/JetBrains/Exposed or https://jdbi.org/ that don't quite... do all the heavy lifting for querying but allow you to sorta stitch queries together manually.

As seems that Micronaut does not include anything similar by default, we use JDBI and that SQL to retrieve one random greeting from the greetings table.

Ah! E sobre o que eu usei no backend, alem de postgres e fly.io, o backend eh eh Java, usando um framework chamado quarkus e jdbi pra fazer a interface com o banco.

More personally, I'm not much an ORM guy. I've just never found that the benefits outweigh the costs, but that's just my opinion. That said, I don't use JDBC directly in my own projects anymore, strongly preferring to use JDBI instead. I find that it walks the line between "make using the database easier" and "get between you and the database" beautifully. But there's not a darn thing wrong with using JDBC directly.