Hibernate database catalog multitenancy

Introduction

As I explained in this article, multitenancy is an architectural pattern which allows you to isolate customers even if they are using the same hardware or software components.

There are multiple ways you can achieve multitenancy, and in this article, we are going to see how you can implement a multitenancy architecture using the database catalog as the unit of isolation.

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How to query parent rows when all children must match the filtering criteria with SQL and Hibernate

Introduction

The Hibernate forum is a never-ending source of inspiration when it comes to solving real-life problems you might bump into when developing an enterprise application.

For instance, this post asks about a JPQL query which should fetch a given parent entity when all its child entities match the given filtering criteria.

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The best way to use SQL functions in JPQL or Criteria API queries with JPA and Hibernate

Introduction

When executing an entity query (e.g. JPQL, HQL or Criteria API), you can use any SQL function without having to register it as long as the function is passed directly to the WHERE clause of the underlying SQL statement.

However, if the SQL function is used in the SELECT clause, and Hibernate has not registered the SQL function (be it a database-specific or user-defined function), you will have to register the function prior to using it in an entity query.

In this article, you are going to learn various ways to register SQL functions with JPA and Hibernate.

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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.

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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.

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