Spring Data JPA Relationships - ManyToMany, ManyToOne & OneToMany
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- čas přidán 7. 07. 2024
- Buy me a coffee: ko-fi.com/boualiali In this video you will understand how to create relations and mapping between you java entity and ensure the same class or database diagram that designed at the beginning.
You will learn the OnToOne relation with unidirectional and bidirectional mapping.
You will learn the ManyToOne and OneToMany relation and it works it details
You will learn the ManyToMany relation and how to implement it
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Table of content
00:00 Introduction
01:22 Join our community
02:05 Presenting the new class diagram
06:13 @OneToOne relation
14:24 @ManyToOne and @OneToMany relation
22:06 @ManyToMany relation
29:07 What comes next?
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How did I not seeing your videos before? Did you know your the only one who explained entire stuff? I will watch your entire list and share your account for those who need. Thanks a lot for great content.
Glad you liked it!
Thank you for that great lesson about Spring Data JPA Relationships.
Glad it was helpful!
Your video is beyond reproach, from theoretical concepts to practical application. Thank you very much for the content, Mr Ali, which is full of pedagogy and enables me to make progress as a beginner with the spring boot framework.
You are most welcome
Thank you so much for this video !! It really helped me a lot !!
Very very good explanation, well simplified, great job!
Glad you enjoyed it!
the only video that made me understand the concept great work
glad to hear that!
Merci beaucoup pour le partage de savoir
My pleasure
Don’t forget to share the video 😄
That was soo helpful. Thank you!
My pleasure
1. You have good well drawn out diagrams and visualizations, it's very helpful
2. Your explanations shows that you have solid fundamentals [Coding + SQL]
3. You gave Practical and Relatable examples.
4. Kudos to you. I am coming from a C++ background, and I appreciate the attention to details in this video. I'll be sure to watch the playlist.
You've got 1 new subscriber here.
Great and detailed feedback.
Happy you liked it!
Thank you Ali for this wonderfull explanation!
You are very welcome
Nice.. Easy to understand. !!!.
Happy to know your feedback 😁
awesome video 🔥 Thank you
Glad you liked it!
Thank you!!!
My pleasure
Great video, this was very helpful
Glad it was helpful!
Thank you Bouali Ali. Would be glad if you can complete this project by creating some Rest Controller class. I hope to see you have more videos about this course.
I already have videos about that. Check the playlist Spring workshops
Please add link
Thanks a lot, really helpful
Happy to know that 🔥
Very Nice video keep the great work up 🙌🙌
Thank you so much 😁
Amazing Tutorial I just joined your discord
Awesome thank you!
Good job , Thanks Ali :)
Always welcome
well done
Thanks
Gold!
Thank you
thank you
My pleasure
good job
Thanks
Would be glad if you can create maybe a single end to end application with spring security included in the app and also learning more about the DTOs
e.g a blog app with several roless
I will consider this idea.
@@BoualiAli yes plz do consider this
@@BoualiAli Please do it
@@inihood i already published a spring security video
New viewer here. I hope 10K subscribers would be a good motivation for you to bring more good content like this !!
Absolutely
Perform CRUD operation in above relationship
Thanks really @Bouli ..can you please make a video/tutorial on making an e-commerce API including uploading product image plus attaching the different prices. Or maybe a destinations API
I really would like to, bit this gonna take so much time. I hope I can do it one day
@@BoualiAli Really thanks. Stay blessed!
Good video but it would be more informative if you showed Crow's foot notation in your visaulisation diagram.
Ok next time
Thank you once again for your dedication with your beautifully explained videos!
I have one question about ManyToMany relationships:
If you need an extra column in the relationship table between (in your case) the Employee and the Mission tables, let's say e.g. a "created_at" column, how would you add it, set it and get it?
Thank you in advance!
Hi there! So, I'm about a month late, and I'm also just getting started with coding, but I solved this situation last week.
In ManyToMany relationships, the intermediate table is generated automatically, which means you can't easily add more attributes without modifying the relationship itself.
The only way I found to resolve this involves actually not using ManyToMany but setting up two OneToMany relationships between employees/missions on the "One" side, linking them to a third entity that contains both IDs along with any extra attributes. Using an example, this would be represented by the EmployeeMission class, which includes employeeId, missionId, and createdAt attributes.
As Ali shows here, for OneToMany relationships, it's important to specify the "mappedBy" annotation, and I also found it helpful to specify the fetch type.
I hope my explanation is clear and helpful. Have a great day!
Amazing content as well, just I wanna ask if the integration of database and diagrams you use exists in STS or intellij community edition or just in intellij ultimate !
Happy you liked it.
Not sure about sts, but for Intellij it is just ultimate version
that's was awesome video
Thank youu
Hi @Bouli for the great tutorials. Could you please make a video about spring security with oauth will appreciate thank you in advance
Already have one about spring security. Check it in the same playlist
@@BoualiAli I did and it is an absolute honour to even talk to you. Where can I reach u out to talk further?
@@kevinameda2711 the honor is mine
You can reach me on our discord server
in all this relationship, which one will auto ipdate the table if one insert happen
SVP comment vous affichez le diagramme de classe représentant les entités dans votre projet Spring Boot avec une base de données ?
Thank you for your help
Thank you too!
Hi,
When we go for Unidirectional mapping and which is best according to requirement?
We can also set the employee id to the address table so why should we address id set to the employee table.
It depends on the logic and needs for your application
I have a problem when inserting an entry with the many-to-one relationship. Lets say i have created a department with the id of 1 in my database and now want to create a employee. I a few cases to do this. 1. By placing the department_id = 1 int the json, 2. by placing the department = 1 in the json, 3. by placing the department equal to the department json from my db entry, 4. by getting the department object from an api call and then employee.setDepartment(department). None worked. Is it not possible to create an Employee by referencing the department id?
when creating an employee you need to set the department object and pass the department is
Here is an example
Department dep = new Department()
dep.setId(departmentId) // the one you get in your request / object / param (depends how you get it)
Employee emp = new Employee()
emp.setField()
emp.set....()
emp.setDepartment(dep)
repository.save(emp)
thank u ! employee_mission was automatically generated in our database , should we create employee_mission class in our entity package or is not necessary ?
if you don't have any extra fields, you don't need to
Thank you so much for such a nice clean video , However I made the simlar entities with one to one bidirectional , when I check the database , it does have each other id as foriein key ,however my app won't start again , but if add something like mapped by employee and add cascade = cascadeType.All , then there won't be two foreign key , there is only one address_id ,but the other foreign key won't appear from the other table ....I am confused
Why your app is not starting after adding one to one?
Can you provide some logs in the discord server (screenshots) to make easier to understand
@@BoualiAli
Yeah I noticed on one to one bidirectional it is better not to provide mapped by on one entity otherwise,otherwise there’s only one foreign key like unidirectional
Tks but when we insert in the table employee , adress_id retuning null
salem khouya ya3tik sa7a 3al vidéo
juste question : OneToMany wel ManyToOne dima relation binéthom unidirectionnelle ???
Thinks can you make a video about MVC architecture
Happy you liked it!
Soon
46th...Thanks
Welcome
Thank you Bouali Ali. This is very concise and really gainful for me. For the one-to-one relationship, in what context is the relationship uni-directional or bi-directional?. Thank You
Unidirectional Relationship: This means that one entity has knowledge of the other, but not vice versa. In other words, if you have two entities, say EntityA and EntityB, and if EntityA has a reference to EntityB (but EntityB does not have a reference to EntityA), then it's a unidirectional relationship.
Unidirectional relationships are simpler and less complex, and are suitable when there is no need for the referenced entity (EntityB in our example) to know about the entity that is referencing it (EntityA). For instance, if you have a User entity and a Profile entity, and each User has one Profile, but a Profile does not need to know which User it belongs to, you can model this as a unidirectional relationship from User to Profile.
Bidirectional Relationship: This is when both entities are aware of each other - EntityA has a reference to EntityB, and EntityB also has a reference to EntityA. This kind of relationship is a bit more complex due to the need to keep both sides of the relationship in sync.
Bidirectional relationships can be useful when there is a need for both entities to be aware of each other. For example, if you have a Customer entity and a BankAccount entity, and each Customer has one BankAccount, but a BankAccount also needs to know which Customer it belongs to, then you would model this as a bidirectional relationship.
Thank you,. how we can achieve ManyToMany relationship whene the join Table should have some data.
You need to create an extra entity that will hold the relation and the extra fields as well
@@BoualiAli could you please create video about that?
@@kamilleskamilless8113 about what exaclty?
Can you help us, full project by using spring boot multipe tables like 3 tables from database
on back end and fetch data to front-end in single table?
aliboucoding.com/courses
can u explain the cascade types
Will note that for the next video
Can anyone tell me what is the function of MappedBy????
How to add database to spring in right panel?
When you create an Entity, you created an Integer field with the "id" annotation.
Can you please clarify why this field should be an Object type and not a primitive one?
Object by default is null
Premitive like int by default 0
You null on the id to help hibernate well manage the entities.
Checkout my new course about spring data jpa and you will understand all this details and master this topic
aliboucoding.com/courses
Bacause we use ArrayList type field to hold MANY objects,
Since ArrayList implements List interface that SUPPORTS only OBJECT TYPE not the primitive type
Can you give me the link of the next video , i can't find it
Spring Data JPA | Hibernate
czcams.com/play/PL41m5U3u3wwkS8BU0fIeRQwY3hK4VlFlX.html
Does OneToMany & OneToMany exist in Spring Boot ?
yes
VIZU ALI ZATION visualization
employee and department uni directional or bi-directional , department table doesnt have any fk of employee
Salut Mr Bouali j'ai une question pertinante pour vous.
le faite de créer une liste lorsqu'on a une annotation @OneToMany dans une classe permet de faire quoi concrètement
Hey,
Amazing content as always, but I have a question about how to use this in "@Repository public interface EmployeeDao extends JpaRepository", for example :
findByEmployeeId and get: Employee Info and his address and his Mission and his Department.
Hi, can explain your question? I didn’t understand
@@BoualiAli how to use join query in spring data jpa, use Employee_Id and get: Employee Info and his address and his Mission and his Department. thank you in advance for your reply. 😀
i am doing this tutorial with pgAdmin 4, and the relation ONETOONE, it's looks like ONETOMANY on my DER
How is that possible?
Can you share some screeshots and code snippets on the discord server?
thanks but you did not explain the difference between unidirectional and bidirectional in @OneToMany @ManyToOne !!
It was already explained in the beginning of the video
Je crois au niveau entity employee tu doid crée comme ceci:@ManyToOne(mapping="employee")
Private collection departmant;
Pourquoi?
@@BoualiAli suivant la cardinalite que vous mentionné dans votre diagramme de class.
@@miloudseo7883 peux tu expliquer plus?
@@BoualiAli clé étranger de la table employee doit etre dans la table départemant car un employee appartient à plusieurs départemant, et chaque départemant ayant une seul employee(ma raisonnement suivant la cardinalité que vous avez mentionné, en uml en raisonne comme ca)
@@BoualiAli je crois tu dois changer la cardinalité entre table employee(*) et departemant(*) to ManyToMany