Hibernate: How to map java.util.Map with java.util.Set as a value with LocalDate inside?

Question

Having an issue with mapping correctly such an object, using annotations:

@Entity
@Table(name = "root_entity")
public RootEntity {
    @Id
    @GeneratedValue
    @Column(name = "id")
    private Long id;

    // annotations here... DayType extends Enum
    private Map<DayType, Set<LocalDate>> days;
}

Wanted result:

root_entity :

column
id
day_types_id

day_types :

column
id
name

days_list :

column
id
localdate_in_typestamp

day_types_to_days_list :

column
day_type_id
day_list_id

Answer 1

You need a DayTypeEntity which would looks something along the lines of the following:

@Entity
@Table(name = "root_entity")
public RootEntity {
    @Id
    @GeneratedValue
    @Column(name = "id")
    private Long id;

    @OneToMany
    @JoinColumn(name = "day_type_id", referencedColumnName = "day_types_id")
    @MapKeyColumn(name = "day_type_id")
    @MapKeyEnumerated(ORDINAL)
    private Map<DayType, DayTypeEntity> dayTypes;
}
@Entity
@Table(name = "day_types")
public DayTypeEntity {
    @Id
    @Column(name = "day_type_id")
    @Enumerated(ORDINAL)
    private DayType id;

    private String name;

    @ElementCollection;
    private Set<LocalDate> days;
}