Databases
StackOverflow2013
Postsdbo
PODeleting an instance of an object with a MANY_TO_MANY relationship without cascading fails
Body
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PODeleting an instance of an object with a MANY_TO_MANY relationship without cascading fails
    text
    copied!<p>I've got two classes (Students and Courses) which have a many-to-many-relationship. Instances of them can exist without the other one. Therefore I removed the cascade-attribute in the JPA-annotation: @ManyToMany(cascade = CascadeType.ALL)</p> <p>Once I try to delete a Student I get this error-message.</p> <p><strong>What am I doing wrong?</strong></p> <blockquote> <p>org.hibernate.exception.ConstraintViolationException: could not delete: [com.Student#4]; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.ConstraintViolationException: could not delete: [com.Student#4]</p> </blockquote> <p>This is the Hibernate-output:</p> <blockquote> <p>Hibernate: delete from student where id=? and version=? 2011-09-19 15:25:10,317 [http-8080-3] ERROR org.hibernate.util.JDBCExceptionReporter - Cannot delete or update a parent row: a foreign key constraint fails (<code>database</code>.<code>student_course</code>, CONSTRAINT <code>FKF8A06F72970A31AF</code> FOREIGN KEY (<code>students</code>) REFERENCES <code>students</code> (<code>id</code>))</p> </blockquote> <p>These are the relevant parts of both classes:</p> <pre><code>@RooJavaBean @RooToString @RooEntity public class Student{ @ManyToMany private Set&lt;Course&gt; courses= new HashSet&lt;Course&gt;(); } @RooJavaBean @RooToString @RooEntity public class Course { @ManyToMany(mappedBy = "courses") private Set&lt;Student&gt; students= new HashSet&lt;Student&gt;(); } </code></pre>
 

Querying!

 
Guidance
An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload