Resin Documentation

creating and removing entity beans

Describes the basic create/remove api for persistent entities.

Demo

Almost all applications need to add and remove entities from the database. Although most database accesses are reads, eventually we need to change the database. With Amber, you create a new instance with the following steps:

1. Instantiate the instance with "new"
2. Populate the values
3. Call the EntityManager ersist method

The example uses the same database table as the previous basic example.

CREATE TABLE create_courses (
  id BIGINT PRIMARY KEY auto_increment,
  course VARCHAR(250),
  instructor VARCHAR(250)
);

Clients create a new bean and populate the fields just like a normal Java object. The client adds the entry to the database by calling the EntityManager's persist method.

...

divination = new Course("Divination", "Sybil Trelawney");
_entityManager.persist(divination);

...

_entityManager.remove(divination);
...

Demo