ByThorben JanssenThe most efficient way to improve the performance of a database query is to avoid it by retrieving the data from a local cache. That’s why Hibernate offers 3 different caches: The 1st level cache contains all entities loaded and created within the current session. The 2nd level cache is a shared, session-independent cache for…
ByThorben JanssenJPA 2.1 introduced the annotation-based Named Entity Graphs and the Entity Graph API. They provide query-independent ways to define which entity attributes Hibernate shall fetch from the database. And while you can’t omit eagerly fetched associations or attributes with Hibernate, you can specify a query-specific eager loading for a graph of associations. Sounds great, doesn’t…
ByThorben JanssenJPA’s @Basic annotation supports a fetch attribute that you can use to define the FetchType of an entity attribute. That seems to be the same approach as you use to define the fetching behavior of an entity association. So, lazy loading of non-relational entity attributes should be easy, right? Well, unfortunately, it isn’t that easy….
ByThorben JanssenIf there is one thing that’s often criticized about JPA and Hibernate, it’s that it sometimes execute more queries than you expected. And I’m not talking about 1 or 2 additional queries. I’m talking about dozens or even hundreds of them. The worst thing about it is that you don’t recognize that problem if you…
ByThorben JanssenWhich data type should you use to map a to-many association with Hibernate? Is it better to use a Set or a List? That’s a very common question, and most developers are surprised when they look at the documentation and find out that these are not the only options. You can also use a Bag…