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Asked: 2026-05-31T12:32:02+00:00

I have simple OneToOne relationship: Data <-> TherapyResult I would like to express the

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I have simple OneToOne relationship:
Data <-> TherapyResult

I would like to express the following constraints
with JPA.

  1. If a Data entity gets removed the associated TherapyResult should be delete,too
  2. If a TherapyResult entity gets removed the associated Data entity should remain in the db

The first constraint is really easy with JPA as I can add CascadingType.REMOVE

@OneToOne(cascade = { CascadeType.REMOVE, CascadeType.REFRESH })
private TherapyResult therapyResult;

For the second constraint I would like to add something like

@JoinColumn(columnDefinition = "DATA_ID BIGINT CONSTRAINT THERAPYRESULTDTAID FOREIGN KEY (DATA_ID) REFERENCES DATA (ID) ON DELETE SET NULL")

However this does not work. OpenJPA seems to have something similiar, but I want to use JPA 2.0 and EclipseLink. OpenJPA ForeignKey.

Another solution would be using @PreRemove described here, which works but looks a bit “none-best-practices” to me. However just a feeling.

My setup is:
Eclipse 3.7.1
EclipseLink 2.3
Apache Derby 10.8.3 and/or HSQLDB

any help is appreciated,
Muki

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1 Answer

  1. Editorial Team

    You can’t use pure JPA to specify foreign keys … that spec doesn’t include the ability. JDO is the only standard with the ability to define FKs. You have to use implementation specifics, or just define the schema yourself and let the JPA impl run on it.

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