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Overview One of the lesser-known yet powerful annotations in Hibernate is @ColumnTransformer. This annotation let us apply SQL transformations on entity properties when interacting with the database. You can think of this annotation as a two way converter. A real life use case Let’s consider a weather app that initially use Kelvin scale to store … Read more
Overview From the official documentation, a Formula mapping defines a “derived” attribute (that means, not persisted), whose state is determined from other columns and functions when an entity is read from the database. You’d probably know other annotation that make a field not persisted to the database: @Transient. While they both allow you to create … Read more
Overview Using @Embedded and @Embeddable in hibernate can help you manage entities and their value type efficiently. The term embed signifies a has-a relationship. For example, in an online game platform, a player has a ranking. In a CRM, a customer has an address. Take the Player and Ranking analogy for example, you can store … Read more
Overview In this article, I will delve into the concepts of candidate keys, primary keys, natural keys, and surrogate keys in the context of Hibernate. Candidate Keys A candidate key is a column or a set of columns in a database table that can uniquely identify each row in the table. It means that candidate … Read more
Overview In this post, we are going to explore the reasons why does Hibernate need a no-arg constructor. The no-arg constructor need to be protected or public. A primer on the no-arg constructor When you declare a class without any constructor, the compiler create a default no-arg constructor for you. However, when you define constructor(s) … Read more
Overview Recently I worked on a web app that needed to call an external API. The web app comprises an Angular (16) client and a Spring Boot (3) server. The call to that external API can be slow (up to 30 seconds). Cases like this are ideal for using multithreading. In this post, I will … Read more