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POparent child relationship implementation
 

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    <p>I'm trying to implement the following <img src="https://i.stack.imgur.com/pU4Rh.png" alt="enter image description here"></p> <p>1 appointment can have 0 to many subAppointments</p> <p>a subAppointment has 1 parent Appointment</p> <p>here is what I've tried:</p> <pre><code>private Appointment parentAppointment; @ManyToMany(cascade = CascadeType.ALL ) private List&lt;Appointment&gt; childrenAppointments; </code></pre> <p>i've also tried some JoinColumn annotations, but it didn't work.</p> <hr> <p>Edit:</p> <p>I've tried Pace's solution -></p> <pre><code>@ManyToOne private Appointment parentAppointment; @OneToMany(cascade = CascadeType.ALL, mappedBy="parentAppointment") private List&lt;Appointment&gt; childrenAppointments; </code></pre> <p>now I've got this error: <code>ERROR: column "appointment_id" appears twice in primary key constraint</code></p> <p>it(Play! Framework) tries to create a table with this script:</p> <pre><code>create table appointment_appointment ( appointment_id integer not null, appointment_id integer not null, constraint pk_appointment_appointment primary key (appointment_id, appointment_id)) ; </code></pre> <hr> <p>Edit2:</p> <p>Fixed by:</p> <pre><code> @ManyToOne @JoinColumn(name = "parent_appointment") private Appointment parentAppointment; @OneToMany( mappedBy="parentAppointment", cascade = CascadeType.ALL) private List&lt;Appointment&gt; childrenAppointments; </code></pre> <p>and </p> <pre><code> public void setParentAppointment(Appointment ap){ this.parentAppointment = ap; } public void addChildAppointment(Appointment ap){ this.childrenAppointments.add(ap); } </code></pre>
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