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@Target(value={METHOD,FIELD}) @Retention(value=RUNTIME) public @interface ManyToOne
Defines a single-valued association to another entity class that
has many-to-one multiplicity. It is not normally necessary to
specify the target entity explicitly since it can usually be
inferred from the type of the object being referenced. If the
relationship is bidirectional, the non-owning
OneToMany
entity side must used the
mappedBy
element to specify the relationship field or
property of the entity that is the owner of the relationship.
The ManyToOne
annotation may be used within an
embeddable class to specify a relationship from the embeddable
class to an entity class. If the relationship is bidirectional, the
non-owning OneToMany
entity side must use the mappedBy
element of the OneToMany
annotation to specify the
relationship field or property of the embeddable field or property
on the owning side of the relationship. The dot (".") notation
syntax must be used in the mappedBy
element to indicate the
relationship attribute within the embedded attribute. The value of
each identifier used with the dot notation is the name of the
respective embedded field or property.
Example 1: @ManyToOne(optional=false) @JoinColumn(name="CUST_ID", nullable=false, updatable=false) public Customer getCustomer() { return customer; } Example 2: @Entity public class Employee { @Id int id; @Embedded JobInfo jobInfo; ... } @Embeddable public class JobInfo { String jobDescription; @ManyToOne ProgramManager pm; // Bidirectional } @Entity public class ProgramManager { @Id int id; @OneToMany(mappedBy="jobInfo.pm") Collection<Employee> manages; }
Optional Element Summary | |
---|---|
CascadeType[] |
cascade
(Optional) The operations that must be cascaded to the target of the association. |
FetchType |
fetch
(Optional) Whether the association should be lazily loaded or must be eagerly fetched. |
boolean |
optional
(Optional) Whether the association is optional. |
java.lang.Class |
targetEntity
(Optional) The entity class that is the target of the association. |
public abstract java.lang.Class targetEntity
Defaults to the type of the field or property that stores the association.
public abstract CascadeType[] cascade
By default no operations are cascaded.
public abstract FetchType fetch
public abstract boolean optional
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Generated on 10-February-2011 12:41