In the tutorial Basic about JPA, I introduced with you all to the JPA configuration file for working with JPA, named persistence.xml. In this tutorial, I will explain more about declaration in this file. As I said before, the persistence.xml file will contain information about… Read More
In the examples of Huong Dan Java on JPA, I often use MySQL as an example because it is free and easy to use, mainly because I’m familiar with it: D. I think some of you, especially the students, often use MSSQL Server. So, I… Read More
When working with JPA, one problem that you might encounter is that the table name in the database is defined in lowercase, but the entity that we declare to define the table name is uppercase or vice versa. For example, I have a table with… Read More
Normally, when we need to manipulate any database we have to write SQL based on the information of the columns, the tables in the database, and possibly for different database types, the syntax of the SQL statement is different. To remove these drawbacks, you guys… Read More
In the previous tutorials part 1 and part 2 about the @GeneratedValue annotation in JPA, I mentioned the allocationSize attribute when using the GenerationType.TABLE and GenerationType.SEQUENCE strategies. Notice that they are not detailed enough for you to understand the allocationSize attribute, so I added this article… Read More
In the case of column name of a table in the database which you are working on is not same with the name of the entity you are defining, you can use the @Column annotation to change the name. Here are some other functions that… Read More
This tutorial is continued part 1. The next strategy we want to talk is the GenerationType.SEQUENCE strategy You declare this strategy in the Clazz entity as follows:
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@Id @GeneratedValue(strategy = GenerationType.SEQUENCE) private Long id; |
Similar to GenerationType.TABLE strategy, GenerationType.SEQUENCE strategy also depends on the value of “hibernate.id.new.generator_mappings” property in the JPA… Read More
When defining a primary key of a table in the database, we usually add AUTO_INCREMENT. With this definition, we do not need to care about the value of the primary key column every time we add a new data to the table, which will be… Read More
In this tutorial, I will cover one of the basic annotations to work with mapping the columns of tables in the database, that is the @Id annotation in JPA. We will go straight into the problem. This annotation is declared to determine where the primary key… Read More
In tutorial basic about Hibernate and basic about JPA, I’ve called classes that map the clazz tables and students in the database as Java objects. But in essence, I have to call them are the entities because they represent tables in the database and each… Read More
