CODEWITHSUNDEEP
javaspring-bootjpa
Dababi
Dababi

Reputation: 185

@ManyToOne mapping between entities without a foreign key constraint. javax.persistence.EntityNotFoundException

I Have an Entity class Certificate which has an Entity class CertificateProfile.

public class Certificate {
    @Id
    private String certId;

    @ManyToOne(fetch=FetchType.EAGER)
    @JoinColumn(name="certificateProfileId", foreignKey = @ForeignKey(name = "none"))
    private CertificateProfile certificateProfile;
}

public class CertificateProfile {
    @Id
    private Long id;

    private String certificateProfileName;
...
}

I'm working with a legacy database. So there is no foreign key constraint even though the certificateProfileId column holds the id of the certificateProfile. When i try to get the certificate list via CertificateDataRepository.findAll(). I get javax.persistence.EntityNotFoundException: Unable to find CertificateProfile with id 0 I tried to set the fetchType to Lazy but I get this error:

could not initialize proxy [CertificateProfileData#1508963102] - no Session

Upvotes: 0

Views: 1586

Answers (2)

Eric
Eric

Reputation: 469

If there is no relation(constraint) between 2 entities at the database level, you do not have to keep the mapping in the class. Remove these 2 lines:

@ManyToOne(fetch=FetchType.EAGER)
@JoinColumn(name="certificateProfileId", foreignKey = @ForeignKey(name = "none"))

and write as follows:

@Column(name="cert_profile_id")
private Long certificateProfileId;

Upvotes: 0

Ken Chan
Ken Chan

Reputation: 90507

It happens in some legacy schema which do not use NULL to indicate the absent of many-to-one entities in the relationship column but instead use some magic value (which I guess in your case this magic value is 0).

By default, Hibernate throws EntityNotFoundException if the many-to-one entities does not exist. You can use Hibernate feature @NotFound to tell Hibernate to ignore this exception and simply assign null to the many-to-one entities reference.

    @ManyToOne
    @NotFound ( action = NotFoundAction.IGNORE )
    @JoinColumn(name="certificateProfileId", foreignKey = @ForeignKey(name = "none"))
    private CertificateProfile certificateProfile;

Upvotes: 4

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