Java Spring Boot - JPA - Hibernate - H2 - Entities Inheritance Mapping - Table Per Class Strategy

In this video we will configure database connection with H2 using spring properties and autoconfiguration. Later we will learn how to use inheritance together with JPA and Hibernate in Java Spring Boot. We will create super class (parent class) and then two sub-classes (child classes) which will inherit all of the properties and mapping information from parent class. We will use @Inheritance annotation to specify strategy which we will use. This time it will be TABLE_PER_CLASS strategy. In the final stage we will learn how to use inheritance in case of repositories which we will use to persist our entities into the database. Also we will check out how to handle mutliple beans implementation using @Primary annotation. We will track everything using H2 web console. Keep coding!
Joined table source code: github.com/codeforgeyt/jpa-in...
Joined table video: • Java Spring Boot - JPA...
Single table source code: github.com/codeforgeyt/jpa-in...
Single table video: • Java Spring Boot - JPA...
Superclass source code: github.com/codeforgeyt/jpa-in...
Superclass video: • Java Spring Boot - JPA...
Table per class source code: github.com/codeforgeyt/jpa-in...
Table per class video: • Java Spring Boot - JPA...
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[@deepusasidharan2012]

Excellent!!!

[@CodeForgeYT]

Many thanks!

[@usermatti]

Thank you Sir

[@huseyinturkmen06]

Really helpful video, i appreciate it!!

[@nhatkhanhly7472]

thank you Sir, Really helpful video! But i have a big problem with 'id' of each table. I want at each table, the id column is restarted at 1. Is it possible?

[@benjamindagenais7461]

Thx for that video, really helpful. What if I have a service and controller Layer, would you create only one class for the 3 classes or you would also have one for each of the child and the parent like the repository ones?

[@CodeForgeYT]

Thanks for feedback! Great question. It really depends on the context. From one side it is nice to follow single responsibility principle and create separated controllers and services for each entity it will be also more versatile in case when some of the entities will have very specific behaviour From the other side it is possible to create some abstraction layer that can handle transformation. Then you can more or less create generic controller and service. So it is all about what you need and how your service will evolve in the future. Keep coding!

[@chebbimehdi8576]

Hello CodeForge i noticed that deleteAll method deletes both tables of the subclasses is there a way to fix this incoherence?

[@CodeForgeYT]

Hi! Probably yes. Depends what you want to achieve. Maybe table per class inheritance is not good for your specific case.

[@chebbimehdi8576]

@@CodeForgeYT Ty for the reply and thank you for all your videos I did fix it by extending each subclass to Jpa itself will that cause a problem in the future if yes what do you advice me to do?

[@CodeForgeYT]

@@chebbimehdi8576 I cant see your code, so it is hard to say if it will cause any problems in the future. If it will, you can simply adapt it later. If you would like to get feedback about your code try on stackoverflow. You can share your code there and discuss it. Glad you like the videos! Keep coding!

[@inwigilator5613]

NULL not allowed for column "ID"; SQL statement: I have @GeneratedValue Annotation

[@CodeForgeYT]

Do you have setter for your id field?