This one time, at band camp, Allan Bond said:
AB>I have a problem updating a many-many relationship in a long
AB>transaction. Basically, I have two objects in a many-many relationship:
AB>
AB>Registration *------* Class
AB>
AB>A user is presented with a static list of Classes (not generated from
AB>the database). After the user submits his selections, I use the classId
AB>to load each of the selected Classes. Then, I add the classes to a new
AB>Registration object and I also add the Registration to the Classes like
AB>this.
AB>
AB> // iterate through selected classes and add them to a new
AB>Registration object
AB> if (c != null) {
AB> for (int x = 0; x < c.length; x++) {
AB> Integer classId = new Integer(c[x]);
AB> Class aClass = new Class();
AB>
AB> // get class from database based on passed ID
AB> try {
AB> db.begin();
AB> aClass =
AB>(Class)db.load(java.lang.Class.forName("net.goldengoal.model.Class"),cla
AB>ssId);
AB> db.commit();
AB> }
AB> catch (Exception e) {e.printStackTrace();}
AB>
AB> // add class to Registration and vice versa
AB> aRegistration.addClass(aClass);
AB> aClass.addRegistration(aRegistration);
AB> }
AB> }
AB>
AB>Then, the user is taken to a confirmation page. After clicking the
AB>'confirm' button, I attempt to update the Registration object like this:
AB>
AB> db.setAutoStore(true);
AB> db.begin();
AB> db.update(aRegistration);
AB> db.commit();
AB>
AB>This works as long as there are no Registrations using the same Class
AB>combination. For example, if I create a Registration that includes
AB>Class A and Class B, it works fine. However, when I try to create
AB>another Registration that includes Class A and Class B, I receive the
AB>following exception:
AB>
AB>org.exolab.castor.jdo.DuplicateIdentityException: update object which is
AB>already in the transaction
Allan,
Because I haven't seen all the code I don't claim to understand the app,
but because you're using setAutoStore( true ), all reachable objects
(meaning all objects in the transaction context) will be stored upon
calling commit(). Is there a reason that you're using this? What happens
when you don't use it?
Also, notice that you're using a key generator. What happens if you
remove the key generator?
Bruce
--
perl -e 'print unpack("u30","<0G)U8V4\@4VYY9&5R\"F9E<G)E=\$\!F<FEI+F-O;0\`\`");'
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