Hi Santiago, Please see the section of the docs titled "Getting an object by key": http://code.google.com/appengine/docs/java/datastore/jdo/creatinggettinganddeletingdata.html#Getting_an_Object_By_Key
-Nick Johnson On Wed, Apr 20, 2011 at 5:43 AM, Santiago Poli <[email protected]>wrote: > Hello everyone. I have a problem when trying to find a single element > by id. The entity class is this: > > @PersistenceCapable(identityType = IdentityType.APPLICATION) > public class Test{ > > @PrimaryKey > private String name; > > ..and so on. > > In this case, the value "name" is acting like an id. I'm using this > query to find the element: > > PersistenceManager pm = > PMF.get().getPersistenceManager(); > > Query q = pm.newQuery(Test.class); > q.setFilter("name == " + category_id); > > //String query = "SELECT FROM " + > JokeCategory.class.getName() + " > WHERE name == " + category_id; > JokeCategory category = (JokeCategory) q.execute(); > > return category; > > But it doesn't retrieve any data. Also, it throws an exception: > java.lang.ClassCastException: > org.datanucleus.store.appengine.query.StreamingQueryResult cannot be > cast to com.santiagopoli.gapptest.domain.Test > > The commented query also doesn't work. > > I hope anyone can help me. Is a shame that something that basic is > difficult to achieve. In other sql implementations, it will be easy as > typing "select * from Test where id=<id>". Thanks! > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > > -- Nick Johnson, Developer Programs Engineer, App Engine -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
