HIBERNATE TUTORIAL

HIBERNATE - Hibernate O/R Mapping

<one-to-one> element

A one-to-one association to another persistent class is declared using a one-to-one element. .

<one-to-one
 

name="propertyName" (1)
class="ClassName" (2)
cascade="cascade_style" (3)
constrained="true|false" (4)
fetch="join|select" (5)
property-ref="propertyNameFromAssociatedClass" (6)
access="field|property|ClassName" (7)
formula="any SQL expression" (8)
entity-name="EntityName"

(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
/> 


(1) name: The name of the property.
(2) class (optional - defaults to the property type determined by reflection): The name of the associated class.
(3) cascade (optional) specifies which operations should be cascaded from the parent object to the associated object.
(4) constrained (optional) specifies that a foreign key constraint on the primary key of the mapped table references the table of the associated class. This option affects the order in which save() and delete() are cascaded, and determines whether the association may be proxied (it is also used by the schema export tool).
(5) fetch (optional - defaults to select): Chooses between outer-join fetching or sequential select fetching.
(6) property-ref: (optional) The name of a property of the associated class that is joined to the primary key of this class. If not specified, the primary key of the associated class is used.
(7) access (optional - defaults to property): The strategy Hibernate should use for accessing the property value.
(8) formula (optional): Almost all one to one associations map to the primary key of the owning entity. In the rare case that this is not the case, you may specify a some other column, columns or expression to join on using an SQL formula. (See org.hibernate.test.onetooneformula for an example.)

A typical many-to-one declaration looks as simple as this:

<many-to-one name="product" class="Product" column="PRODUCT_ID"/>


Hibernate tutorial
Introduction to Hibernate
Overview of Hibernate
Features of Hibernate
Getting Started with Hibernate
Hibernate O/R Mapping

Mapping declaration

Mapping Document
<hibernate-mapping> element
<class> element
<id> element
<generator> element
<property> element
<many-to-one> element
<one-to-one> element
Hibernate Mapping In Depth
Hibernate Query Language
Hibernate Complete Example

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