Tag Archives: JPA

JPA provides several alternatives for querying data. Such alternatives may be classified attending to a variety of criteria, eg, language used (SQL vs JPQL) or whether queries are static (compilation time) or dynamic (execution time). Static queries are defined using annotations @NamedQuery (javax.persistence.NamedQuery) and @NamedQueries (javax.persistence.NamedQueries) in the @Entity class definition itself:         @NamedQuery( name="findAllCustomersWithName", query="SELECT c ...

Introduction In my previous post I introduced the entity state transitions Object-relational mapping paradigm. All managed entity state transitions are translated to associated database statements when the current Persistence Context gets flushed. Hibernate’s flush behavior is not always as obvious as one might think.       Write-behind Hibernate tries to defer the Persistence Context flushing up until the last ...

JPA identifier generators JPA defines the following identifier strategies:                 Strategy Description AUTO The persistence provider picks the most appropriate identifier strategy supported by the underlying database IDENTITY Identifiers are assigned by a database IDENTITY column SEQUENCE The persistence provider uses a database sequence for generating identifiers TABLE The persistence provider uses a ...

The N+1 problem is a common issue when working with ORM solutions. It happens when you set the fetchType for some @OneToMany relation to lazy, in order to load the child entities only when the Set/List is accessed. Let’s assume we have a Customer entity with two relations: a set of orders and a set of addresses for each customer. ...

This post was written together with +Aslak Knutsen (@aslakknutsen). JPA type converters provide an easy way to define how an entity attribute gets persisted to the database. You can use them to implement lots of different features, e.g. to encrypt your data as I showed in a previous post: How to use a JPA Type Converter to encrypt your data. ...

A few days ago, I read an interesting article by Bear Giles about Database encryption using JPA listeners from 2012. He discusses his requirement for an encryption solution and provides a code example with JPA listeners. His main requirements are: provide a transparent encryption that does not affect the application, be able to add the encryption at deployment time, develop ...

This is my second post on JPA 2.1 Entity Graphs. The first post described the usage of named entity graphs. These can be used to define a graph of entities and/or attributes at compile time that shall be fetched with a find or query method. Dynamic entity graphs do to the same but in a dynamic way. This means you can ...

Persisting enums with JPA 2.0 is possible, but there is no nice way to do it. Using the @Enumerated annotation, you can use EnumType.ORDINAL or EnumType.STRING to map the enum value to its database representation. But both options have some drawbacks, that we will discuss in the first part of this article. In the second part, I will show you ...

In this article we will see how to configure and integrate SpringMVC4, Spring Data JPA with Hibernate and SpringSecurity using JavaConfig. 1. First let’s configure all the necessary dependencies in pom.xml                 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.sivalabs</groupId> <artifactId>spring-javaconfig</artifactId> <version>1.0</version> <packaging>war</packaging> <name>SpringApp JavaConfig Demo</name> <properties> <java.version>1.7</java.version> <junit.version>4.11</junit.version> <slf4j.version>1.7.5</slf4j.version> <logback.version>1.0.13</logback.version> <spring.version>4.0.0.RELEASE</spring.version> <spring-data-jpa.version>1.4.1.RELEASE</spring-data-jpa.version> <spring-security.version>3.2.0.RELEASE</spring-security.version> ...