CODEWITHSUNDEEP
javadatabasejpaenums
F_Schmidt
F_Schmidt

Reputation: 1132

How can I map multiple enums into the same column in java spring?

I have a field in a model object which takes an enum like this:

@Enumerated(...)
private UniveritySubject subject; //Of course not working like this...

For a better structure and a better overview I want to separate my subject in two enums: One enum representing winter and one enum representing summer subjects like this:

public class Subject {

    public enum Summer {
        ...
        MATH;
    }

    public enum Winter {
        ...
        PHYSICS;
    }
}

How can I achieve the mapping of either of those enums to the model column subject? Sadly it is not possible to inherite enums, so I can not have a "superclass enum". I thought about using one enum with boolean value isInWinter, but please regard that I have a lot of subjects and I think it isn't good to overview. Is there any other solution?

Upvotes: 0

Views: 1357

Answers (1)

pirho
pirho

Reputation: 12235

To normalize this a bit I would change the design. UniversitySubject should be an entity of its own, like (for example):

@Entity
public class UniversitySubject {
    @Enumerated(EnumType.STRING)
    private Season season;
    @Enumerated(EnumType.STRING)
    private Subject subject;
}

where Season is:

enum Season { SPRING, SUMMER, AUTUMN, WINTER }

and Subject

enum Subject { MATH, PHYSICS, BIOLOGY }

and then in the class using it would be like

@ManyToOne
private UniversitySubject subject;

Also, to clarify things a bit maybe UniversitySubject could be named TermSubject or something alike?

Of course it is possible to use JPA annotations for example to concat all this stuff into one string and parse back but small changes in the design should make these 'hacks' unnecessary.

Upvotes: 1

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