A beginner’s guide to the Hibernate JPQL and Native Query Plan Cache
Introduction Every JPQL query must be compiled prior to being executed, and, because this process might be resource-intensive, Hibernate provides a QueryPlanCache for this purpose. For entity queries, the query String representation is parsed into an AST (Abstract Syntax Tree). For native queries, the parsing phase cannot compile the query, so it only extracts information about the named parameters and query return type.
How do find and getReference EntityManager methods work when using JPA and Hibernate
Introduction While doing my High-Performance Java Persistence training, I realized that not all developers are familiar with the getReference method of the JPA EntityManager and most of them use find almost exclusively. In this article, we are going to see the difference between the find and getReference method so that it’s clear when to apply them depending on the underlying use case.
MariaDB 10.3 supports database sequences
Introduction Traditionally, both MySQL and MariaDB relied on AUTO_INCREMENT columns to generate an IDENTITY Primary Key. Although IDENTITY columns are very efficient in generating the Primary Key value, when it comes to using JPA and Hibernate, the IDENTITY generator prevents us from using JDBC batch inserts. To automatically enroll multiple INSERT, UPDATE or DELETE statements, Hibernate requires delaying the SQL statement until the Persistence Context is flushed. This works very well for the SEQUENCE identifier since the entity identifier can be fetched prior to executing the INSERT statement. However, for IDENTITY columns,… Read More
How to synchronize bidirectional entity associations with JPA and Hibernate
Introduction While answering this StackOverflow question, I realized that it’s a good idea to summarize how various bidirectional associations should be synchronized when using JPA and Hibernate. Therefore, in this article, you are going to learn how and also why you should always synchronize both sides of an entity relationship, no matter if it’s @OneToMany, @OneToOne or @ManyToMany.
How to avoid the Hibernate Query Cache N+1 issue
Introduction I recently answered this question on the Hibernate forum, and since it’s a very good one, I decided to turn it into an article. In this post, we will describe how the N+1 query issue is generated when using the second-level Hibernate Query Cache.
9 High-Performance Tips when using PostgreSQL with JPA and Hibernate
Introduction To get the most out of the relational database in use, you need to make sure the data access layer resonates with the underlying database system. In this article, we are going to see what you can do to boost up performance when using PostgreSQL with JPA and Hibernate.
How to map an immutable entity with JPA and Hibernate
Introduction In this article, you are going to find out how to map an immutable entity when using JPA and Hibernate. If your Domain Model requires that a given entity should not be modified by the data access logic, Hibernate can enforce this requirement if the entity is marked with the @Immutable annotation.
PostgreSQL SERIAL or IDENTITY column and Hibernate IDENTITY generator
Introduction When using PostgreSQL, it’s tempting to use a SERIAL or BIGSERIAL column type to auto-increment Primary Keys. PostgreSQL 10 also added support for IDENTITY, which behaves in the same way as the legacy SERIAL or BIGSERIAL type. This article will show you that SERIAL, BIGSERIAL, and IDENTITY are not a very good idea when using JPA and Hibernate.
How to use a JVM or database auto-generated UUID identifier with JPA and Hibernate
Introduction In this article, we are going to see how to use a UUID entity identifier that is auto-generated by Hibernate either in the JVM or using database-specific UUID functions. Our Post entity looks as follows: The Post entity has a UUID identifier and a title. Now, let’s see how we can map the Post entity so that the UUID identifier be auto-generated for us.
