Unexplainable OneToOneWithoutMapsIdEvent with unidirectional one-to-one

[pkernevez]

I have the following message, I can't understand: CRITICAL - OneToOneWithoutMapsIdEvent - The [fees] one-to-one association in the [InstrumentEntity] entity is using a separate Foreign Key to reference the parent record. Consider using @MapsId so that the identifier is shared with the parent row. For more info about this event, check out this User Guide link - https://vladmihalcea.com/hypersistence-optimizer/docs/user-guide/#OneToOneWithoutMapsIdEvent

I try to have a unidirectional one-to-one, and maps the parent ID as the child PK. This is my configuration:

@Entity
@Table(name = "INSTRUMENT")
public class InstrumentEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SEQ_INSTRUMENT")
    @SequenceGenerator(name = "SEQ_INSTRUMENT", sequenceName = "SEQ_INSTRUMENT", allocationSize = 1)
    private Long id;

    @OneToOne(fetch = FetchType.LAZY, orphanRemoval = true, cascade = CascadeType.ALL)
    @SuppressWarnings({"java:S1948", "Serializable because of CurrencyEntity"})
    @JoinColumn(name = "INSTRUMENT_FEE_ID")
    @MapsId("ID")
    private InstrumentFeeEntity fees;

}

And

@Entity
@Table(name = "INSTRUMENT_FEE")
public class InstrumentFeeEntity {

    @Id
    private Long id;
}

Should I miss something or is it a false positive error ?

[vladmihalcea]

Try using @MapsId not @MapsId("ID").

Also, create an integration test and activate the hbm2ddl tool to let Hibernate create the schema for you. If Hibernate creates a separate FK, then the mapping was not working properly.

[vladmihalcea]

@pkernevez I also tested the @MapsId("ID") mapping, and it's not taken into consideration by Hibernate, falling back to a separate FK.

The fact that Optimizer caught the issue is great because it shows it works. Just try it with @MapsId and see for yourself.