About entities

manual

JPA Persistable Types

Explains how JPA manages types, including entity classes, embeddable classes, primitive types, wrappers, string, date, enum, collections and maps.... or java.util.Map can be used when storing entities. If an unsupported collection or map type is used, ObjectDB will ... working with ObjectDB. Proxy Classes When entities are retrieved from the database, instances of mutable persistable ...

 
manual

Storing JPA Entity Objects

Explains how to use JPA to store (persist) entity objects in the database.... can only be stored in the database embedded in containing entities (as field values). A TransactionRequiredException ... Clear the persistence context, causing all managed entities to become detached. See JavaDoc Reference Page... ( ...

 
manual

Retrieving JPA Entity Objects

Explains how to use JPA to retrieve entity objects from the database. The Java Persistence API (JPA) provides various ways to retrieve objects from the database. The retrieval of objects does not require an active transaction because it does not change the content of the database. The persistence context se ...

 
manual

Deleting JPA Entity Objects

Explains how to use JPA to delete (remove) entity objects from the database.... (Optional) Whether to apply the remove operation to entities that have been removed from the relationship and to cascade the remove operation to those entities. See JavaDoc Reference Page... = true ) ...

 
api-jpa

javax.persistence.Entity

Specifies that the class is an entity.(Annotation of JPA)

 
manual

Defining a JPA Entity Class

Shows how to define a JPA entity class in order to store objects in the database. To be able to store Point objects in the database using JPA we need to define an entity class . A JPA entity class is a POJO (Plain Old Java Object) class, i.e. an ordinary Java class that is marked (annotated) as having the ability to represent ...

 
tutorial

Step 2: Entity Class and Persistence Unit

Explains how to define a JPA entity class and a persistence unit (persistence.xml) in a NetBeans Java EE 6 web application. To store objects in an ObjectDB database using JPA we need to define an entity class: Open the [New Entity Class] dialog box, e.g. by right clicking the project node (in the [Projects] window) and selecting New > Entity Clas ...

 
tutorial

Step 2: Entity Class and Persistence Unit

Explains how to define a JPA entity class and a persistence unit (persistence.xml) in a NetBeans Spring MVC web application project. To store objects in an ObjectDB database using JPA we need to define an entity class: Open the [New Entity Class] dialog box, e.g. by right clicking the project node (in the [Projects] window) and selecting  New > Entity Class ... (or  New ...

 
manual

JPA Primary Key

Explains how to define and use primary keys in JPA, including composite and embedded primary keys.... by their primary key as shown in the Retrieving Entities section. Embedded Primary Key An alternate way to ... to Event objects in the database because references to entities hold primary key values) and is less efficient in store operations. ...

 
manual

Detached Entity Objects

Explains detached entity objects and how to work with detached objects in JPA, including merging them into an EntityManager.... Clear the persistence context, causing all managed entities to become detached. See JavaDoc Reference Page... method, ...