Introduction When fetching an entity, all attributes are going to be loaded as well. This is because every entity attribute is implicitly marked with the @Basic annotation whose default fetch policy is FetchType.EAGER. However, the attribute fetch strategy can be set to FetchType.LAZY, in which case the entity attribute is loaded with a secondary select statement upon being accessed for the first time. This configuration alone is not sufficient because Hibernate requires bytecode instrumentation to intercept the attribute access request and issue the secondary select statement on demand.
The survey Java Persistence API is a standard. Hence, there are multiple options to choose from: Hibernate EclipseLink OpenJPA Some applications choose not to use an ORM framework at all. For this reason, I decided to run a one-day survey on Twitter to get a glimpse on the JPA providers market share.
Introduction In this article, we are going to see how we can build an entity in a fluent style API fashion when using JPA and Hibernate. The JHipster development team wants to expose a Fluent Interface entity building methods for their JPA entities, so they asked me if this is going to work with JPA and Hibernate. While JPA is rather strict about entity getters and setter, Hibernate is more lenient in this regard.
Introduction One of my readers asked me to help him map a Composite Primary Key using JPA and Hibernate. Because this is a recurrent question, I decided to write a blog post in which I describe this mapping is more detail.
Introduction There are many ways you can map a one-to-one relationship with Hibernate. In this post, I’m going to demonstrate which mapping is the most efficient one from a database perspective.
Introduction In this article, I’m going to explain how the persist and merge entity operations work when using JPA and Hibernate. When using JPA, entity state transitions are translated automatically to SQL statements. This post is going to explain when to use persist and when to use merge.
Introduction In this article, I’m going to show you various high-performance Java Persistence optimization tips that will help you get the most out of your data access layer. A high-performance data access layer requires a lot of knowledge about database internals, JDBC, JPA, Hibernate, and this post summarizes some of the most important techniques you can use to optimize your enterprise application. 1. SQL statement logging If you’re using a framework that generates statements on your behalf, you should always validate the effectiveness and efficiency of each executed statement. A testing-time assertion… Read More
Introduction The Open Session in View is an Anti-Pattern, and this post is going to demonstrate why it is so. First of all, let’s start with the Wikipedia definition of an Anti-Pattern: An anti-pattern (or antipattern) is a common response to a recurring problem that is usually ineffective and risks being highly counterproductive.
Introduction This article is part of a series of posts related to calling various relational database systems stored procedures and database functions from Hibernate. The reason for writing this down is because there are many peculiarities related to the underlying JDBC driver support and not every JPA or Hibernate feature is supported on every relational database.