Creating Mappings with Hibernate XML Files - Beginning Hibernate: From Novice to Professional - page 157

The set Collection
A set collection allows collection attributes derived from the Set interface to be persisted.
In addition to the common collection mappings, the <set> element offers the inverse ,
order-by , and sort attributes, as shown in Table 7-11.

Table 7-11. The Additional <set> Attributes

Attribute Values Default Description

inverse true , false false Specifies that an entity is the opposite navigable end of

a relationship expressed in another entity's mapping.

order-by Specifies an arbitrary SQL order by clause to constrain

the results returned by the SQL query that populates
the set collection.

sort Specifies the collection class sorting to be used. The

value can be unsorted , natural , or any Comparator
class.

The child elements of the <set> element are as follows:

(meta*,
subselect?,
cache?,
synchronize*,
comment?,
key,
(element | one-to-many | many-to-many |
composite-element | many-to-any),
loader?,
sql-insert?,
sql-update?,
sql-delete?,
sql-delete-all?,
filter*)

The following code shows an implementation of mapping a set of strings into a property
called titles :

<set name="titles" table="nameset">
<key column="titleid"/>
<element type="string" column="name" not-null="true"/>
</set>

A typical implementation, however, maps other entities into the collection. Here we map
Phone entities from the “many” side of a one-to-many association into a Set property, called
phoneNumbers , that belongs to a User entity: