Annotation Type ManyToOne
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@Target({METHOD,FIELD}) @Retention(RUNTIME) public @interface ManyToOne
Specifies 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-owningOneToMany
entity side must used themappedBy
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-owningOneToMany
entity side must use themappedBy
element of theOneToMany
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 themappedBy
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; }
- Since:
- 1.0
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Optional Element Summary
Optional Elements Modifier and Type Optional Element Description 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.Class
targetEntity
(Optional) The entity class that is the target of the association.
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Element Detail
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targetEntity
Class targetEntity
(Optional) The entity class that is the target of the association.Defaults to the type of the field or property that stores the association.
- Default:
- void.class
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cascade
CascadeType[] cascade
(Optional) The operations that must be cascaded to the target of the association.By default no operations are cascaded.
- Default:
- {}
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fetch
FetchType fetch
(Optional) Whether the association should be lazily loaded or must be eagerly fetched. The EAGER strategy is a requirement on the persistence provider runtime that the associated entity must be eagerly fetched. The LAZY strategy is a hint to the persistence provider runtime.- Default:
- jakarta.persistence.FetchType.EAGER
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