Hibernate JPA @CollectionTable Example

@CollectionTable

The @CollectionTable annotation is used to specify the database table that stores the values of a basic or an embeddable type collection.

@CollectionTable is used for the mapping of collections of basic or embeddable types. Applied to the collection-valued field or property.
By default, the columns of the collection table that correspond to the embeddable class or basic type are derived from the attributes of the embeddable class or from the basic type according to the default values of the Column annotation. In the case of a basic type, the column name is derived from the name of the collection-valued field or property. In the case of an embeddable class, the column names are derived from the field or property names of the embeddable class.

To override the default properties of the column used for a basic type, the Column annotation is used on the collection-valued attribute in addition to the ElementCollection annotation.
To override these defaults for an embeddable class, the AttributeOverride and/or AttributeOverrides annotations can be used in addition to the ElementCollection annotation. If the embeddable class contains references to other entities, the default values for the columns corresponding to those references may be overridden by means of the AssociationOverride and/or AssociationOverrides annotations.
If the CollectionTable annotation is missing, the default values of the CollectionTable annotation elements apply.

    Example:

    @Embeddable public class Address {
       protected String street;
       protected String city;
       protected String state;
       ...
     }

    @Entity public class Person {
       @Id protected String ssn;
       protected String name;
       protected Address home;
       ...
       @ElementCollection  // use default table (PERSON_NICKNAMES)
       @Column(name="name", length=50)
       protected Set<String> nickNames = new HashSet();
       ...
    }

    @Entity public class WealthyPerson extends Person {
       @ElementCollection
       @CollectionTable(name="HOMES") // use default join column name
       @AttributeOverrides({
          @AttributeOverride(name="street",
                             column=@Column(name="HOME_STREET")),
          @AttributeOverride(name="city",
                             column=@Column(name="HOME_CITY")),
          @AttributeOverride(name="state",
                             column=@Column(name="HOME_STATE"))
        })
       protected Set<Address> vacationHomes = new HashSet();
       ...
    }