Java & PostgreSQL - using them together?
Hi,
I can understand Java and PostgreSQL in isolation. However, I struggle with understanding how I can combine the two. Both the basics of how to do it (I heard something called JDBC, and also Doobie but perhaps thats only Scala, but didn't learn it so far), but also how to know WHEN to use the SQL and when to write Java code.
For example, I might want to connect my Java program to a database that stores all the users of a bank account. I would like to be able to fetch the users balance at a given date, but it would be horribly slow if all of it was done in Java, so we would have to create some kind of database in PostgreSQL.
This is an easy example, but in other cases I don't have any real guidestick (syntactically, algorithmatically, and architecture/system design wise) to know when to write Java code and when to write PostgreSQL code, and how to combine them.
Any course or material is appreciated. For example if you know a good udemy course that teaches this or something else (perhaps neetcode? but maybe he doesnt teach postgreSQL).
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Unknown User•13mo ago
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Yes that much is clear, but I was looking for some sort of course that goes through JDBC/JPA for Java & PostgreSQL. My difficulty is to know how to properly combine both of them to make a performant program.
I already know PostgreSQL and Java in isolation, and I could probably learn how to use JDBC/JPA to connect them in no time. But how do I know if I should write some Queries to get the data, or some pure java code? And how do I actually write that code properly inside Java (and not just SQL queries in Pgadmin)? Hopefully some beginner course exist on this :)
If I were to write pure java code that would fetch all of an accounts bank transactions from the database it would be really inefficient. A better way would be to write some SQL query inside the java code, that simply executes
select * from tablename (simplification). Of course, this is an easy case, but I hope you understand that I am looking for better understanding of how to write programs that is performant and scalable.
I.e. I am confused on the actual implementation logic, and need some basic course that goes through this :) something more than isolated potsgresql, and isolated java course, but a combination of the two.I mean it depends, if you want to go for full performance, you can go for raw JDBC, but it will be quite painful 😄
There's layers on top that map your tables to objects, like hibernate etc, that are still pretty fast, but it all depends on the use case ofc
I've done some raw imports of stack overflow dumps, and I do those in pure JDBC, with some code I wrote around it, but it's quite a handful. Then I'm actually limited by the database
Unknown User•13mo ago
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spring-jpa begs to differ? 😄
"magic"
Unknown User•13mo ago
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findByName(String name)
Yeah, but I don't have to write SQL(sorry for not being concise and bad at formulating my confusion but its because this area is totally unclear to me right now :p )
I am looking for something very basic, like super fundamental and beginner level, that somehow teaches me how to write actual code (whatever that code is, like I don't know "you cannot write pure java code that would fetch...", I am a step lower in that in my understanding, and don't know JDBC/JPA/etc). I can write some simple pure java programs, and some simple pure database in postgresql with some isolated queries there.
I didn't reach further than this in my understanding. Now when I want to make a simple banking program (nothing fancy) in Java, i would have to store the data in a database whenever a user interacts with a simple business logic inside my java program.
Do you know if there exist some udemy or other course that teaches me how to combine a database with java, and how to know when to write what and how to do it in a performant way? (probably 99% of what I wrote is a misunderstanding or wrong angle, but I hope you understand what sort of knowledge/course I am looking for)
Unknown User•13mo ago
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It depends, do you WANT to write SQL manually, or are you more adventurous and looking for a slightly more convenient way of accessing the database?
I am looking for the industry standard of what is needed in the real world :) to be employable
ah, that would be the spring framework
With hibernate
Unknown User•13mo ago
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Ok thanks so I will have to google "java intro to jdbc" and find topics on this :)
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Unknown User•13mo ago
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nope why?
Baeldung
Learn JPA & Hibernate | Baeldung
A series of tutorials on the core features of JPA and Hibernate.
Unknown User•13mo ago
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Baeldung has good java stuff
is it too formal? :) haha
Unknown User•13mo ago
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danish and english
Unknown User•13mo ago
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So I will be best served to learn the Spring framework with JPA hibernate
to be a better fit for the industry
Last 7 jobs I had were in those two technologies
spring-boot more specifically
Unknown User•13mo ago
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JPA is a rabbithole, and it is DEEP
Unknown User•13mo ago
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I often hear people speak about Spring and Spring boot, and then JPA and JDBC
yeah
so if I know Java and PostgreSQL at a fundamental level, a logical next step would be to learn Spring (not spring boot**) with JPA (not JDBC) right?
spring boot, which is a framework
Ah
Spring boot and JPA
Of those 7 I've had one that uses "base" spring
The 6 others were boot
Unknown User•13mo ago
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Ok I will learn about JDBC, then "Spring Boot + JPA"
Entity here, repository there, 90% of your database needs covered
Unknown User•13mo ago
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Thanks
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Unknown User•13mo ago
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They finally figured out microservices are a sham 😄
Here's my plan for learning:
1. Refresh Data Structures & Algorithms on Java (already doing right now)
2. Refresh PostgreSQL
3. JDBC
4. dependency injection
5. Spring Boot
6. JPA Hibernate
Unknown User•13mo ago
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maybe stick jdbc and hibernate a bit closer together
but yeah
Oh true they are connect haha
1. Refresh Data Structures & Algorithms on Java (already doing right now)
2. Refresh PostgreSQL
3. dependency injection
4. Spring Boot
5. JDBC
6. JPA Hibernate
Unknown User•13mo ago
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Ty for the tiops
and I will subscribe to laur spilca
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