Thank you, Nick,
I have written code as below with low level API to delete the entry.
It runs without error but seems not totally working. And thanks god
that data suddenly appeared at Data Viewer and problem resolved.
Code pasted here and hope it useful for others
import com.google.appengine.api.datastore.DatastoreService;
import com.google.appengine.api.datastore.DatastoreServiceFactory;
import com.google.appengine.api.datastore.Entity;
import com.google.appengine.api.datastore.Query;
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws IOException {
String tbname = req.getParameter("tbname");
if(tbname!=null)
{
DatastoreService datastore =
DatastoreServiceFactory.getDatastoreService();
// Or perform a query
Query query = new Query(tbname);
for (Entity taskEntity :
datastore.prepare(query).asIterable()) {
datastore.delete(taskEntity.getKey());
}
}
}
Regards,
Charlie
On Jun 17, 11:58 pm, "Nick Johnson (Google)" <nick.john...@google.com>
wrote:
> Hi Charlie,
>
> Your easiest option here is probably to upload an alternate major version of
> your app with the old schema, and use that to retrieve and fix the faulty
> entit(y|ies). Alternate approaches include using the low level datastore
> API, or uploading a Python version that uses the low level API or
> db.Expando.
>
> -Nick Johnson
>
>
>
>
>
> On Wed, Jun 17, 2009 at 9:15 AM, Charlie Zhu <zh.char...@gmail.com> wrote:
>
> > Hi,
>
> > I have tried all ways I known to delete some schema changing caused
> > error Entities and failed.
>
> > 1. Delete on Data Viewer on the console.
> > Data Viewer shows "No Data Yet."
>
> > 2. Delete by code
> > Below is part of the codes:
> > Query q = pm.newQuery(CDKFingerprint.class);
> > List<CDKFingerprint> results2;
> > results2 = (List<CDKFingerprint>) q.execute();
> > pm.deletePersistentAll(results2);
> > But that cause server error:
> > java.lang.NullPointerException: Datastore entity with kind
> > CDKFingerprint and key CDKMol(c=cc=cc=c)/CDKFingerprint(1) has a null
> > property named bits_count. This property is mapped to
> > cdkhelper.CDKFingerprint.bits_count, which cannot accept null values.
> > ...
> > at org.datanucleus.jdo.JDOPersistenceManager.deletePersistentAll
> > (JDOPersistenceManager.java:795)
> > ...
>
> > 3. Assign values to the NULL field then delete
> > The code
> > for(CDKFingerprint r: results2) {
> > r.bits_count = 0;
> > pm.makePersistent(r);
> > }
> > And server error again
> > java.lang.NullPointerException: Datastore entity with kind
> > CDKFingerprint and key CDKMol(c=cc=cc=c)/CDKFingerprint(1) has a null
> > property named bits_count. This property is mapped to
> > cdkhelper.CDKFingerprint.bits_count, which cannot accept null values.
> > ...
> > at org.datanucleus.store.appengine.query.StreamingQueryResult
> > $AbstractListIterator.hasNext(StreamingQueryResult.java:205)
> > ...
>
> > Having no idea and hoping help.
>
> > Regards,
> > Charlie
>
> --
> Nick Johnson, App Engine Developer Programs Engineer
> Google Ireland Ltd. :: Registered in Dublin, Ireland, Registration Number:
> 368047
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Google App Engine" group.
To post to this group, send email to google-appengine@googlegroups.com
To unsubscribe from this group, send email to
google-appengine+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/google-appengine?hl=en
-~----------~----~----~----~------~----~------~--~---
