CODEWITHSUNDEEP
javahibernatejpaenumsmany-to-many
Raild
Raild

Reputation: 933

JPA enumerated entity with ManyToMany relationship

I have two entities with many-to-many relationship. My database structure:

Document    Status                  Document_Status
╔════╗      ╔════╦══════════╗       ╔═════════════╦═══════════╗
║ id ║      ║ id ║  status  ║       ║ document_id ║ status_id ║
╠════╣      ╠════╬══════════╣       ╠═════════════╬═══════════╣
║  1 ║      ║  1 ║ STORED   ║       ║           1 ║         1 ║
║  2 ║      ║  2 ║ APPROVED ║       ║           2 ║         1 ║
║  3 ║      ╚════╩══════════╝       ║           3 ║         2 ║
╚════╝                              ╚═════════════╩═══════════╝

And I want to use enum for Status.

public enum Status {
    STORED, APPROVED
}

@Entity
public class Document {

    @Id
    @GeneratedValue
    private long id;

    // ??
    private Set<Status> statuses;
}

I've tried to implement it this way, but the solution ignores Status table and tries to create statuses from status_id in EnumType.ORDINAL way:

@ElementCollection(targetClass = Status.class)
@CollectionTable(name = "Document_Status", joinColumns = @JoinColumn(name = "document_id"))
@Column(name = "status_id", nullable = false)
private Set<Status> statuses;

@Enumerated(EnumType.STRING) also doesn't help. It starts to find value with name "1" in Status enum.

I could wrap the enum into entity like recommended here. But isn't it possible to be implemented without creation of wrapper entity?

Upvotes: 2

Views: 1832

Answers (2)

jklee
jklee

Reputation: 2268

You need only a wrapper, if you will a join table and identify the enumy by id. You do not need this all.

Document    Status            

╔════╗      ╔═════════════╦═════════════╗ 
║ id ║      ║ Document_id ║  statuses   ║ 
╠════╣      ╠═════════════╬═════════════╣ 
║  1 ║      ║  1          ║ STORED      ║   
║  2 ║      ║  2          ║ APPROVED    ║ 
║  3 ║      ║  2          ║ STORED      ║ 
║  4 ║      ║  3          ║ APPROVED    ║ 
║  5 ║      ╚═════════════╩═════════════╝ 
╚════╝                        


public enum Status {
    STORED, APPROVED
}

@Entity
public class Document {

    @Id
    @GeneratedValue
    private long id;


    @ElementCollection
    @Enumerated(EnumType.STRING)
    private Set<Status> statuses;
}

Upvotes: 1

mibrahim.iti
mibrahim.iti

Reputation: 2060

I think you should edit your Entities to be like that

Status

@Entity
public class Status {

    public enum StatusEnum {
        STORED, APPROVED
    }

    @Id
    @GeneratedValue
    private Integer id;

    @Enumerated(EnumType.STRING)
    @Column(name = "status")
    private StatusEnum status;
}

Document

@Entity
public class Document {

    @Id
    @GeneratedValue
    private long id;

    @ManyToMany
    private Set<Status> statuses;
}

Upvotes: 3

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