SQL is an incredibly powerful query language. It provides sheer endless possibilities to extract and transform information. One example of that is a window function. It enables you to perform operations on subsets of the table rows available in your query. The PostgreSQL documentation explains window functions as: A window function performs a calculation across a set…
Since the release of Java’s record feature, I got asked how you could use records with Hibernate. Until Hibernate 6, I had to tell you that JPA and Hibernate only supported records as DTO projections. That finally changed with the release of Hibernate 6.0 and got even easier with Hibernate 6.2. Unfortunately, you still can’t use…
The JPA specification and Hibernate, as its most popular implementation, claim to provide database portability. That means you don’t need to change your persistence code or mapping annotations when connecting your application to a different RDBMS. They achieve that by providing an automated object-relational mapping, an API that abstracts from the executed SQL statements, and…
Most developers prefer numerical primary keys because they are efficient to use and easy to generate. But that doesn’t mean that a primary key has to be a number. UUIDs, for example, have gained some popularity over recent years. The main advantage of a UUID is its (practical) global uniqueness which provides a huge advantage…
Some of Hibernate’s core features are automatic dirty checks, flushes, and the 1st level cache. They make the implementation of most standard use cases simple and efficient. But they also add a lot of hidden complexity and are not a great fit for all use cases. Your typical nightly import job or most other use…