How do you get the primary key values in your application? Do you use natural keys or do you generate technical IDs? I prefer to generate simple, numerical, technical IDs like you can see in the following code snippet instead of using natural keys which often require the combination of multiple attributes. @Id private Long…
Do JPA and Hibernate really fit the project you’re about to start? This important question gets not asked often enough! And if you don’t think about it in the beginning, it will be difficult to change your mind after the project starts. Most often, the persistence framework gets selected based on personal preferences. And while…
Representing associations between entities as attributes is one of the most comfortable and popular features of JPA and Hibernate. It makes it very easy to navigate from one entity to one or more associated entities in your Java code, like from a Person entity to the corresponding Address entity. You can also use the association…
JPA supports a set of database functions which you can use to perform small operations and transformations within a query. This is often easier and faster than doing it in the Java code. But how do you call functions which are not supported by the JPA standard, like database-specific ones or the custom functions implemented…
Loading related entities with JPA and Hibernate is a comfortable feature that is also the most common reason for performance issues. In most applications you can find one of these two issues: related entities are eagerly loaded, even if they are not needed or related entities are lazily loaded which creates n+1 select issues if…