In this tutorial, as the tutorial introducing basic about Hibernate, not lengthy, I will go straight to an example of JPA with the implementation of Hibernate to give you a first look and understand how JPA works. First, I will create a Maven project as… Read More
Before going into the JPA tutorials, I think I need to clarify the differences between JPA and Hibernate because I see if most of you did not understand thoroughly, will not distinguish the difference between them. JPA stands for Java Persistence API, which is a… Read More
Anyone who wants to learn about JPA needs to know about the concept of Object Relational Mapping. So what is it actually? Suppose, you are working on an application and your application uses a table named users in the database. The structure of this table… Read More
In the previous tutorial, I showed you how to represent a Composite Primary Key in JPA using the @Embeddable annotation. In addition to this, we also have a way to represent the Composite Primary Key in JPA which is using the @IdClass annotation. How is… Read More
In the previous tutorial, I introduced you to the @ManyToMany annotation to express many-to-many relationships between any two tables in the database, such as a developer can work on multiple projects and vice versa: a project can have many developers. But in fact, we need… Read More
Composite Primary Key is a table containg two or more columns Primary Keys. To represent them by entity in JPA, we can use the @Embeddable annotation. How is it in details? Let’s find out in this tutorial. First, I will create a Maven project as… Read More
In this tutorial, we will research together on a final annotation in JPA, beside @ManyToOne, @OneToOne, @OneToMany annotation, to express the relationship between any two tables in the database. That is the annotation @ManyToMany! In case, any two tables have many-many relationships, such as a… Read More
Suppose, you are working on a project where the database has two tables, such as student and clazz, structured like below:
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CREATE TABLE `clazz` ( `id` int(11) NOT NULL, `name` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; CREATE TABLE `student` ( `id` int(11) NOT NULL, `name` varchar(255) DEFAULT NULL, `clazz_id` int(11) DEFAULT NULL, PRIMARY KEY (`id`), FOREIGN KEY (`clazz_id`) REFERENCES `clazz` (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; |
As you can see, the clazz table has columns id and name with the primary key id. Student table has columns id, name… Read More
Annotation @ManyToOne in JPA is used to express multiple-to-one relationships between two tables in a database. There are many records in table A related to a record in table B. For example: many different students may have the same class. In this tutorial, we will… Read More
In JPA, to express one relationship to another, for example, a tourist can have a single room in a large hotel, we will use the @OneToOne annotation. How is it in details? In this tutorial, let’s learn about annotation @OneToOne in JPA! First, I will… Read More
