Hibernate Annotations

1. Java 1.5 only

Only Java 1.5 supports annotations. If you are using 1.4 you can use xdoclet to help generated your mapping files

http://annotations.hibernate.org/

2. Basic column mapping

unique column restraint

To specifiy an unique key constraint on a column use


    @Column(unique=true)

Enumeration

Enums are saved as either text or ordinals depending on the underlying column.

Ignored or transient fields

To ignore the field, annotate it with @Transient so it will not be mapped by hibernate.

3. Cascade all-delete-orphan

The standard EJB annotations don't have the delete orphan option.


@OneToMany {cascade=CascadeType.ALL}

The above is from the javax.persistence package.

Instead we can still use the original Hibernate mapping attributes this way:


@org.hibernate.annotations.Cascade(
   {org.hibernate.annotations.CascadeType.ALL,org.hibernate.annotations.CascadeType.DELETE_ORPHAN}
)