CODEWITHSUNDEEP
javajpaorm
user1278890
user1278890

Reputation: 663

JPA entity, identify Business key

Lets say I'm writing a JPA entity. Very simple one. It has 3 properties:

public class MenuItem {
    @Id
    @GeneratedValue
    private Long menuItemId;

    @Column(nullable = false)
    private String name;

    @Column(nullable = false)
    private Type type;

    @OneToOne(cascade = {CascadeType.ALL})
    @JoinColumn(name = "colorId")
    private Color color;
}

Now, lets say I need to override its equals/hashcode methods. According to this suggestion Implementing equals() and hashCode() I have to use some sort of "Business key equality". But I have doubts, what should I consider as a "Business" key here. Does it have to be all the properties except of ID, or Color can be excluded from it. Just seems unclear to me. Would be thankful if anyone can explain more on this topic.

Upvotes: 3

Views: 1307

Answers (1)

Maciej Kowalski
Maciej Kowalski

Reputation: 26572

The last statement in the reference is pure gold:

Note that a business key does not have to be as solid as a database primary key candidate. Immutable or unique properties are usually good candidates for a business key.

So in your case name and type would be good candidates. Assuming the Type would be an immutable object (you could still get away without that but you might experience some hard to detect bugs).

IF you would put a unique constraint on color then i would consider that in the equals / hashCode method also.

Upvotes: 3

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