Thanks Tristan,
I made the proper code adjustments, but unfortunately JDO is not aware
of the Entity relationship.
Is there a certain way I can use to make JDO consistent with low level
API keys ?
On Jun 13, 4:08 pm, Tristan <tristan.slomin...@gmail.com> wrote:
> It's possible to do anything in low-level API :)
>
> Although your code wouldn't work because you don't have question key
> available, and you need to include transaction parameter in your puts.
>
> It would need to be something like
>
> Transaction txn = dataStore.beginTransaction();
> Key key = dataStore.put(txn, question);
> Entity a1 = new Entity("Answer", key);
> Entity a2 = new Entity("Answer", key);
> dataStore.put(txn, a1);
> dataStore.put(txn, a2);
> txn.commit();
>
> But it would probably make more sense to combine the answer puts:
>
> Transaction txn = dataStore.beginTransaction();
> Key key = dataStore.put(txn, question);
> Entity a1 = new Entity("Answer", key);
> Entity a2 = new Entity("Answer", key);
> List<Entity> as = new ArrayList<Entity>(2);
> as.add(a1);
> as.add(a2);
> dataStore.put(txn, as);
> txn.commit();
>
> On top of that, if you know what the keys should be, (if you're naming
> them with strings), then you could probably do it more efficiently
> with one put
>
> Key questionKey = KeyFactory.createKey("Question", "question1");
> Key answer1Key = KeyFactory.createKey(questionKey, "Answer",
> "answer1");
> Key answer2Key = KeyFactory.createKey(questionKey, "Answer",
> "answer2");
> Entity question = new Entity(questionKey);
> Entity answer1 = new Entity(answer1Key);
> Entity answer2 = new Entity(answer2Key);
> List<Entity> entities = new ArrayList<Entity>(3);
> entities.add(question);
> entities.add(answer1);
> entities.add(answer2);
> Transaction txn = dataStore.beginTransaction();
> dataStore.put(txn, entities);
> txn.commit();
>
> The other thing you need to make sure is that JDO understands low-
> level API keys and relationships that you code and that persistance
> manager doesn't rewrite them in some way. (I don't know an answer to
> that).
>
> Cheers.
>
> On Jun 12, 11:03 am, luka <uluk...@gmail.com> wrote:
>
> > Hi,
>
> > My application is currently using JDO, although for some stress
> > testing
> > I am trying to employ batch insert using low level API (since it is
> > less practical to do it with JDO).
>
> > I have JDO parent-child one to many model which I am trying to insert
> > using the low level API "Entity" model.
> > So far I have succeeded to batch insert the entities although failed
> > in making the relationship.
>
> > Is it possible to accomplish a parent-child one to many relationship
> > using Entity API ?
>
> > Short Example:
> > -------------------
> > // One Question has Many Answers
>
> > @PersistenceCapable (detachable = "true")
> > public class Question implements Serializable {
>
> > �...@primarykey
> > @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
> > @Extension(vendorName="datanucleus", key="gae.encoded-pk",
> > value="true")
> > private String key;
>
> > �...@persistent(mappedBy = "question")
> > @Element(dependent = "true")
> > private List<Answer> answers;
>
> > ......
>
> > }
>
> > @PersistenceCapable (detachable = "true")
> > public class Answer implements Serializable {
>
> > @PrimaryKey
> > @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
> > @Extension(vendorName="datanucleus", key="gae.encoded-pk",
> > value="true")
> > private String key;
>
> > �...@persistent
> > private Question question;
>
> > ....
>
> > }
>
> > // Using low level API
>
> > Entity question = new Entity("Question");
>
> > Entity a1 = new Entity("Answer",question.getKey());
> > ....
> > Entity a2 = new Entity("Answer",question.getKey());
> > ...
>
> > DatastoreService dataStore =
> > DatastoreServiceFactory.getDatastoreService();
> > Transaction txn = dataStore.beginTransaction();
> > dataStore.put(question);
> > dataStore.put(a1);
> > dataStore.put(a2);
> > txn.commit();
>
> > //END
>
> > Thanks
> > Luka
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