About JPA

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Manual
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CRUD Operations with JPA

The following subsections explain how to use JPA for CRUD database operations:
Manual
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JPA Query Structure (JPQL / Criteria)

The syntax of the Java Persistence Query Language (JPQL) is very similar to the syntax of SQL. Having a SQL like syntax in JPA queries is an important advantage because SQL is a very powerful query language and many developers are already familiar with it. The main difference between SQL and JPQL
JPA Doc
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JPA Annotations for Callback Methods

The following annotations can mark methods as JPA callback methods: The Lifecycle Events section of the ObjectDB Manual explains how to use all these annotations on callback methods and with listener classes.
JPA Doc
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JPA Annotations for Relationships

Relationships are persistent fields in persistable classes that reference other entity objects. The four relationship modes are represented by the following annotations: Unlike ORM JPA implementations, ObjectDB does not enforce specifying any of the annotations above. Specifying a relationship
JPA Doc
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JPA Metamodel API Types

The following interfaces and enum represent types in the JPA Metamodel API:  See the Metamodel Type Interface Hierarchy section for more details and examples.
Manual
36

Storing JPA Entity Objects

setting the ObjectDB configuration or in a JPA portable way, by specifying the cascade-persist XML
Manual
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JPA Lifecycle Events

Callback methods are user defined methods that are attached to entity lifecycle events and are invoked automatically by JPA when these events occur. Internal Callback Methods Internal callback methods are methods that are defined within an entity class. For example, the following entity class
JPA Doc
36

JPA Metamodel API Attributes

The following interfaces and enum types represent attributes (persistent fields and properties) in the JPA Metamodel API: See the Metamodel Attribute Interface Hierarchy section for more details and examples.
Manual
36

Advanced JPA Topics

This section discusses advanced JPA topics:
Tutorial
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Step 2: Define a JPA Entity Class [2011-02-11]

To store objects in an ObjectDB database using JPA we need to define an entity class: Open the [New Java Class] dialog box, e.g. by right clicking the project node (in the [Package Explorer] window) and selecting New > Class. Enter tutorial as the package name - use exactly that case sensitive