Why you should always use hibernate.connection.provider_disables_autocommit for resource-local JPA transactions
Introduction One of my major goals for Hibernate is to make sure we offer all sorts of performance improvements to reduce transaction response time and increase throughput. In Hibernate 5.2.10, we addressed the HHH-11542 Jira issue which allows you now to delay the database connection acquisition for resource-local transactions as well. In this article, I’m going to explain how Hibernate acquires connections and why you want it to delay this process as long as possible.
Best way to map the JPA and Hibernate ManyToMany relationship
Introduction In this article, I’m going to show you the best way to map a ManyToMany association when using JPA and Hibernate. As simple as JPA annotations might be, it’s not always obvious how efficient they are behind the scenes.
How to install DB2 Express-C on Docker and set up the JDBC connection properties
Introduction While developing Hibernate, I need to test the code base against a plethora of relational database systems: Oracle, SQL Server, PostgreSQL, MySQL, MariaDB, Informix, and of course DB2. However, having all these databases installed on my system is far from ideal, so I rely a lot on Docker for this task. In this article, I’m going to show how easily you can install DB2 on Docker and set up the JDBC connection so that you can run Hibernate tests on DB2.
The best way to do batch processing with JPA and Hibernate
Introduction Recently, one of my followers asked me to answer a question on Quora about batch processing, and, since the question was really interesting, I decided to turn it into a blog post. In this article, you are going to find out what batch processing is, why do we use it, and how to use it properly with JPA and Hibernate.
How does a JPA Proxy work and how to unproxy it with Hibernate
Introduction In this article, I’m going to explain how JPA and Hibernate Proxy objects work, and how you can unproxy an entity Proxy to get access to the underlying POJO instance. The JPA lazy loading mechanism can either be implemented using Proxies or Bytecode Enhancement so that calls to lazy associations can be intercepted and relationships initialized prior to returning the result back to the caller. Initially, in JPA 1.0, it was assumed that Proxies should not be a mandatory requirement, and that’s why @ManyToOne and @OneToOne associations use an EAGER loading… Read More
Why you should use the Hibernate ResultTransformer to customize result set mappings
Introduction JPA queries allow you to fetch either entities or DTO projections. However, sometimes you want a combined result set as illustrated in this Hibernate forum question.
The best way to map a @OneToMany relationship with JPA and Hibernate
Introduction While adding a @OneToMany relationship is very easy with JPA and Hibernate, knowing the right way to map such an association so that it generates very efficient SQL statements is definitely not a trivial thing to do. In a relational database system, a one-to-many association links two tables based on a Foreign Key column so that the child table record references the Primary Key of the parent table row. As straightforward as it might be in a relational database, when it comes to JPA, the one-to-many database association can be represented… Read More
How to find which statement failed in a JDBC Batch Update
Introduction Yesterday, my Danish friend, Flemming Harms, asked my a very interesting question related to when a JDBC batch update fails. Basically, considering we are going to group several DML statements in a batch, we need a way to tell which statement is the cause of the failure. This post is going to answer this question in more detail.
