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
    
      manages;
     }