1515 days That’s how much time it took me from the moment I started this blog, until I became a Java Champion. In this article, I’m going to show you what I did so that, after 1515 days, I became the first Java Champion from Romania.
Introduction Someone asked me to answer the following StackOverflow question, and, because the question is very interesting from an SQL perspective, I decided to turn the answer it into a blog post. In this article, we are going to see how to map a JPA @ManyToOne association to the result of a SQL query using the Hibernate-specific @JoinFormula annotation.
How to emulate @CreatedBy and @LastModifiedBy from Spring Data using the @GeneratorType Hibernate annotation
Introduction Hibernate comes with many additions to the standard JPA specification. One such example is the @GeneratorType annotation which allows you to customize the way a given entity property value is automatically generated. If you’re using Spring Data, you can simply use the @CreatedBy and @LastModifiedBy annotations and the annotated entity properties are going to be populated with the currently logged user. If you’re not using Spring Data, then you can easily emulate the same behavior using the Hibernate-specific @GeneratorType annotation and the ValueGenerator callback mechanism.
Introduction Last week, one of my blog readers asked me of a way to reuse the @Id mapping so that it won’t have to be declared on each an every entity. Because this is a good opportunity to introduce @MappedSuperclass, I decided to answer the question with a blog post.
Introduction Last week, Burkhard Graves asked me to answer the following StackOverflow question: And, since he wasn’t convinced about my answer: I decided to turn it into a dedicated article and explain how UPSERT and MERGE work in the top 4 most common relational database systems: Oracle, SQL Server, PostgreSQL, and MySQL.