About EntityManager
Database Connection using JPA
Describes the main JPA interfaces: EntityManagerFactory, EntityManager and EntityTransaction.... Overview EntityManagerFactory EntityManager EntityTransaction Overview A connection to a database is represented by an EntityManager javax.persistence.EntityManager JPA interface ...
Obtaining a JPA Database Connection
Shows how to use Java/JPA to connect to the ObjectDB Object Database. In JPA a database connection is represented by the EntityManager javax.persistence.EntityManager JPA interface Interface used to interact with the ...
Storing JPA Entity Objects
Explains how to use JPA to store (persist) entity objects in the database.... invoking the persist persist(entity) EntityManager's method Make an instance managed and persistent. See ... ; em. getTransaction getTransaction() EntityManager's method Return the resource-level EntityTransaction object. ...
Detached Entity Objects
Explains detached entity objects and how to work with detached objects in JPA, including merging them into an EntityManager.... special state in which they are not managed by any EntityManager javax.persistence.EntityManager JPA interface Interface used to interact with the ...
CRUD Operations with JPA
Explains how to use JPA for CRUD database operations (persist, retrieve, update, remove). The following subsections explain how to use JPA for CRUD database operations: Storing JPA Entity Objects Retrieving JPA Entity Objects Updating JPA Entity Objects Deleting JPA Entity Objects ...
Retrieving JPA Entity Objects
Explains how to use JPA to retrieve entity objects from the database.... combination of its class and its primary key. Given an EntityManager javax.persistence.EntityManager JPA interface Interface used to interact with the ...
Deleting JPA Entity Objects
Explains how to use JPA to delete (remove) entity objects from the database.... by invoking the remove remove(entity) EntityManager's method Remove the entity instance. See JavaDoc ... be deleted using the remove remove(entity) EntityManager's method Remove the entity instance. See JavaDoc ... = em. find find(entityClass, primaryKey) EntityManager's method Find by primary key. See JavaDoc Reference ...
Should derived fields of an EmbeddedId be manually maintained by app code?
If I have an Entity which has a primary key which is derived and I am implementing it using @EmbeddedId, am I responsible for maintaining the derived fields of the @EmbeddedId? I could not find anything in the JPA 2.0 spec http://download.oracle.com/auth/otn-pub/jcp/persistence-2.0-fr-oth-JSpec/persistence-2_0-final-spec.pdf?e=1317047713&h=54831c176e81a244a4c309e13eba0b27 which tells me what to expect. ... . Entity ; import javax. persistence . EntityManager ; import javax. persistence . FlushModeType ... public static EContainer getInstance ( EntityManager em ) { EContainer c = em. find ...
Updating JPA Entity Objects
Explains how to use JPA to delete (remove) entity objects from the database.... = em. find find(entityClass, primaryKey) EntityManager's method Find by primary key. See JavaDoc Reference ... em. getTransaction getTransaction() EntityManager's method Return the resource-level EntityTransaction object. ...
Conflicting modifiers .... (javax.persistence.Id, javax.persistence.ManyToOne)
I have two classes a Container type class and another class that is 'contained' by that class. The contained class, CompoundKeyMapItem, represents an alternate implementation of an object held in a Map, and uses a Compound Primary Key. The contained class therefore uses an @IdClass. This all works fine on Eclipselink. However when I try and run this in ObjectDb I get the following error; ... . Entity ; import javax. persistence . EntityManager ; import javax. persistence . FlushModeType ... public static Container getInstance ( EntityManager em ) { Container c = em. find ( ...
