When we’ve discussed the inheritance and mapped superclasses concepts in the previous tutorials, we are avoiding concepts that could confuse the readers or makes misunderstanding for them. Most of the clarified examples didn’t provide an Abstract Entity as a target entities that can be managed by the entity manager. On the contrary an Abstract Entity was only …
JPA
EclipseLink / JPA Annotations – @AttributeOverride And @AssociationOverride
At this tutorial we’ll introduce using of @AttributeOverride and @AssocationOverride that mentioned intentionally at the @MappedSuperclass tutorial. As you’ve remembered at @MappedSuperclass annotation tutorial, we’ve mentioned at the Database Design section the possibility of using @AttributeOverride and @AssociationOverride to override the attributes and associations that inherited from the mapped superclass. An entity can inherit a persistent entity state and …
EclipseLink / JPA Annotations – @Inheritance With Joined Table Strategy
In the Java Persistence API (JPA) The entities support inheritance, polymorphic, polymorphic associations, and polymorphic queries. Both abstract and concrete classes can be entities, and both of them can be annotated with the @Entity annotation, mapped as entities and queried for as entities. Entities can extend non-entity classes and non-entity classes can extend entity classes, so …
EclipseLink / JPA Annotations – @Inheritance With Single Table Strategy
In the Java Persistence API (JPA) The entities support inheritance, polymorphic, polymorphic associations, and polymorphic queries. Both abstract and concrete classes can be entities, and both of them can be annotated with the @Entity annotation, mapped as entities and queried for as entities. Entities can extend non-entity classes and non-entity classes can extend entity classes, so …
EclipseLink / JPA Annotations – @ManyToMany
The Many-To-Many annotation is one of the most important annotations provided by the EclipseLink – JPA. It defines a many-valued association with ManyToMany multiplicity (See single-valued multiplicity and different kind of many-valued multiplicity). A newly concept has introduced such as (JoinTable) as well as a new annotation like (@JoinTable) when we are coming to introduce …
EclipseLink / JPA Annotations – @OneToOne
OneToOne annotation is one of the annotations that are used for defining a single-valued association to another entity that has one-to-one multiplicity. The multiplicity concept seems ambiguous but it simply tells you the maximum and minimum allowed members of the set. It is a UML design concept for defining the association relationship, in one-to-one case …
EclipseLink – JPA Annotations
Have you ever been standing up close to an article that list most of the annotations that are used by the EclipseLink – JPA API? The EclipseLink provides many annotations covering the persistence into databases. But when we are coming into use of these annotations, we have already faced a big obstacles while remembering those …
EclipseLink – Configuration error. Class [com.mysql.jdbc.Driver] not found [javax.persistence.PersistenceException]
The EclipseLink – JPA API is persistence service that provided a standard way to communicate with the database. The major important issue needs to take care of while development of a project using a JPA, is a database driver that can help the JPA communicates with the suggested database. This post will cover a proper …