Using JSF with Entity Relationships - EJB 3.0 Database Persistence with Oracle Fusion Middleware 11g - page 314

Define a @OneToMany relationship to the Section entity. Set the cascade element
to CascadeType.ALL to cascade all operations to the target of the association. The
mappedBy element specifies the field that owns the relationship. In a one-to-many
relationship the many-side must be the owning side of the relationship, which in
the example is the Edition entity. The fetch element specifies the fetch strategy.
The default strategy is LAZY , which does not fetch the associated entities when an
entity is retrieved. LAZY fetching is useful if an entity has a number of associations,
which further have associations and all that is required is a particular entity. But, as
we require the associated entities too, set fetch strategy to EAGER , which fetches all
the associated entities. Specify a join table for the one-to-many mapping using the @
JoinTable annotation. The name element of the @JoinTable specifies the table name.
The name element is optional and defaults to the concatenated names of the two
associated primary entity tables The joinColumns element specifies the foreign key
columns of the join table that are mapped to the primary table of the owning entity,
and the inverseJoinColumns element specifies the foreign key columns of the
join table that reference the table for the non-owning entity. The joinColumns and
inverseJoinColumns are also optional and default values are used if not specified.
The one-to-many mapping for the edition-section relationship is as follows:
@OneToMany(cascade = CascadeType.ALL, mappedBy = "edition",fetch =
FetchType.EAGER)
@JoinTable(name = "Edition_Section", joinColumns = {
@JoinColumn(name = "edition_section_id",
referencedColumnName = "id")} ,
inverseJoinColumns = {
@JoinColumn(name = "section_id",
referencedColumnName ="id")} )
Specify the getter/setter methods for the Section entity:
public List<Section> getSections() {
return sections;
}
public void setSections(List<Section> sections) {
this.sections = sections;
}
Also add methods to add and remove a Section entity:
public void addSection(Section section) {
this.getSections().add(section);
section.setEdition(this);
}
public void removeSection(Section section) {
this.getSections().remove(section);
}