I’m not suggesting that to use RDBMS you should know how to administrate and tune it (though it helps), but knowing their language, and understanding a single data structure (B+ trees) isn’t too much to ask, I think.
In some cases, but the more frequent issue I saw back in the day was the DBA making some really complex schema tuned for what they wanted, then an application trying to use the data in a pretty reasonable OOP manner (1 to many relationships, etc) and the DBA pissed they were using an ORM instead of their perfect SQL queries and procedures.
Tbh, I don't understand why this is seen as a bad thing. Correction: I know why it is (any changes are obviously going to be dramatically slowed down), but in the long run, I don't understand why people are against it. You wanted something done correctly, so you went to the SME for that specific field, and had them do it for you. Then you decided to throw it away?! Why are you bothering to ask them in the first place?
> 1 to many relationships, etc
I know this was just an example, but 1:M is a perfectly natural part of any RDBMS, and in no way requires an ORM to be done.
Usually this was a mismatch of mgmt or expectations. Hiring old school DBAs and letting them think they "own the data", while plopping them into a huge dev team changing the big SaaS features daily is a recipe for trouble.
I don't fault DBAs per se, though I did work with some who wouldn't look outside their blinders at all.
The mapping of database results to java objects with Hibernate is convenient. The basic "load entity, change a couple fields, let Hibernate persist it" flow is convenient. In a limited set of cases, basic entity graph navigation is convenient.
As I said, if you're working in an object-based language, by definition you need something that maps relations to objects. Hibernate is a competent choice. There are other competent choices, but JDBC is not one of them unless your app is trivial.
Anyways. Hibernate works on top of JDBC, so, if you like its interface, then it means you could make your own, but skipping >99% of the rest of Hibernate code that has nothing to do with wrapping the driver.
Or, imagine there was a library Hibernate', that threw away all the ORM stuff, and only offered mapping of SQL results to Java objects and sending queries to the database. Then, why not use Hibernate' instead of Hibernate?
NB. About triviality. From experience: trivial apps tend to work OK with ORM. Non-trivial will usually ditch the ORM because of performance, missing functionality and general difficulty with servicing it. So, it's the other way around: if you are shooting for the stars, you are probably not going to use Hibernate, Hibernate is one of the variety of tools that helps losers loose less, it's not a tool for the winners.
I think you've built up a strawman in you mind of what you think "ORM" is. Yes Hibernate is huge and has a lot of features that people shouldn't use. But you can say the same about Microsoft Word, the problem is that everyone uses a different 5% of the huge feature set.
People who work with these technologies on a daily basis don't screw up the core acronyms. I suggest softening your opinion and dropping the platitudes.
BTW. I'm absolutely on-board with you: nobody should use Microsoft Word. There's absolutely no reason to do that. It's a marketing ploy with a lot of grease money paid to people in charge of procurement in various places. It's absolutely not about 5% of features. It's just downright worst kind of text editor that's in popular use today. Ask me how I know this? I worked in a newspaper! Somehow, Microsoft never ventured into this field, and didn't sell their garbage there. And nobody uses Microsoft in book publishing or any other sort of publishing. Not for any % of its features. So much so that if you bring a manuscript (as an outside author) to publish a book or an article in a newspaper / magazine, and it will be in MS Word format, you'll be most likely asked to convert it to another format. And we are talking about people who need a lot of different features of text editing!
And, I really don't care about what you have to suggest. You aren't in a position to make suggestions really ;)
My go to metaphor has been "XYZ is an angry 800lb gorilla sitting between you and your work."
If you start with a network data model perspective and build that into your system, then it follows that you'll want a network data model to SQL mapper. That's what ORMs are, and the need for them comes from your approach, not from the tools you use.
There's a different approach - use OOP to build computational abstractions rather than model data. Use it to decompose the solution rather than model the problem. Have objects that talk to the database, exchange sets of facts between it and themselves, and process sets of facts. In the process, you can also start viewing data relationally - as n-ary relations over sets of values - as opposed to binary relationships between tables of records.
Information systems are not domain simulations, simulations compute the future state of the domain whereas information systems derive facts from known facts at the present time.
For a visual metaphor, car engineers don't use roadmaps as design diagrams and they don't model the problem domain in the systems they build. A car isn't built from streets, turns, road signs, traffic lights, etc. And despite that, cars function perfectly well in the problem domain. A car generally doesn't need to be refactored and reassembled when roads or rules change.
It's infinitely easier and less error-prone to keep the interface between the database and the application to the minimum (just convert the final results of a query to the application objects and embed complete queries in the application code) than to try and create complex query builders behind the scenes of object-to-object interaction.
If you want to make a good product, you may start with ORM, as it may, for a time, delay the need of understanding the relationship between the application and the database, and allow you to experiment faster at the expense of lost performance. Once you know what you need to do, ORM just no longer works: you will have to break it at least in order to deal with performance issues, but often you will also find yourself dealing with the fact that a lot of what you want to express in your queries is either too difficult or even impossible to express in a particular ORM.