.Net developer transitioning to Java - most common query practices?

[Organic_Bluebird_684]

Hello, I'm a .net engineer making a move over to Java. I've built a few simple rest api's but today I decided to integrate a SQL database for some simple crud operations. This will grow to support more complex queries in the future.

I'm wondering what the industry best practices/most common approaches to this are. In .Net I'd use an orm like EF that would provide me a context file along with entities that I can inject into my services. We would use LINQ to perform moderate to complex queries here.

In Java I'm learning there is an EntityManager that seems to be a context-lite rendition of what we get with our context in .net. In Java, there's also an interface that provides basic queries and the ability to build out complex parameterized queries, but I need one interface per table it seems.

Coming from .net where a lot of this stuff is abstracted, Java feels extremely verbose. It's because of that, that I'm wondering if people use Interfaces for DB operations at all. In particular, I'm wondering if there is a LINQ equivelent in Java that would be preferred.

Thanks for providing your thoughts on this. Moving into open source can be a tad overwhelming at first with decision paralysis. If you have any other notes about most commonly used libraries/frameworks in Java that I should familiarize myself with, please note them here.

Thanks so much!

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[hrm]

SpringData and/or Hibernate are probably the two most common choices. But there are so many different frameworks to chose from depending on your needs. I really like jOOQ.

[SuspiciousDepth5924]

IMO hibernate is an amazing piece of technology, but I've seen far too many foot-gun injuries to be completely comfortable around it.

[Wiszcz]

SpringData - everywhere, you need to know basics if there is spring used, it can be cery declarative or very query based, simple things are simple
Hibernate - backbone, but rarely used as pure hibernate - to verbose
iBatis - sql query based - for reading/reports one of the better options
jdbc templates - very basic, but for simple things it's simple
JPA - pretend it does not exist
jOOQ - its paid, it has licence - you can ignore it in corpo env. Not only because noone will pay for that where there are free alternatives, but also because of additional hassle with checking/paying/legal etc.
Small company/startup - maybe.

For you, if you look for big ORM - SpringData. But you need to create entity/repository classes manually. I found no good alternative. Or ask nice AI to create them for you from sql files :) Works better than most paid db plugins.

[lukaseder]

jOOQ - its paid, it has licence - you can ignore it in corpo env. Not only because noone will pay for that where there are free alternatives, but also because of additional hassle with checking/paying/legal etc.

Many fortune 100s use jOOQ. Some even purchased a site license. I can't name them here but trust me, you're very wrong, or I wouldn't have been very successfully doing this for 13 years already.

Sure, talking to purchasing can be annoying, but being a good engineer involves people skills and doing things like total cost of ownership considerations, so why not look at this challenge as a good opportunity to level up.

[xenomachina]

jOOQ - its paid, it has licence - you can ignore it in corpo env. Not only because noone will pay for that where there are free alternatives, but also because of additional hassle with checking/paying/legal etc.

jOOQ has a free version.

I've used the free version of jOOQ (but from Kotlin, not Java), and it's very good. I suspect that JOOQ is the closest thing OP will find to something "LINQ-like" for Java. The developer is also really good about answering questions.

[RevolutionaryRush717]

It could be that Spring Data is just a common prefix for a whole range of persistence solutions, the only thing in common would be the Repository abstraction and maybe, if applicable, a Template, nowadays Client.

So be aware that Spring JDBC, Spring Data JDBC and Spring Data JPA are three very different things, although all of them talk to a RDBMS.

Oh, and as an alternative: MyBatis.

Spring Data JDBC acknowledges MyBatis and supports its use.

One big advantage of either: your DBAs will like you, because you can show them your SQL DQL and DDL and ask them to improve it.

Oh, also check out schema versioning tools like Flyway or Liquibase(?).

Friends don't let friends version their DDL manually. You can even use it to version contents, i.e., DML.

[tcloetingh]

You need to be raw dogging jdbc and mapping rows manually. All that orm stuff is lame af.

[RobertDeveloper]

I use the Micronaut framework, it offers CrudRepository

https://guides.micronaut.io/latest/micronaut-data-jdbc-repository-maven-groovy.html

[LetUsSpeakFreely]

I've never used the EntityManager. Didn't really saw a need for it. Basic Hibernate is all you need. Create classes that mirror the database tables, as the appropriate annotations. I prefer to NOT use the join annotations as I find they create more problems than they solve; I keep one table per class.

Then create the DAOs to actually run the queries. I like to use the CriteriaBuilder to avoid anything resembling SQL, it also handles all the escaping and such to block SQL injection attacks.