Thanks Ikai for 1.
Will definitely refer to the link in 2. and get back if I have more
questions.
Thanks for the quick help.
On Mon, Dec 21, 2009 at 9:38 AM, Ikai L (Google) ika...@google.com wrote:
1. If you just delete all the entities of a single Kind, it is the same
effect as deleting a table. You have to remember that the datastore is not
SQL. Underneath the hood, it is a schemaless key-value store. Type
information is defined within each entity itself and in the corresponding
indexes.
2. The solution that seems to fit for the most developers is to do multiple
queries and join in memory. Another solution can be to precompute the result
at write time and denormalize your schema so that you query on the
denormalized field. Without knowing what you are doing, it can be difficult
to recommend any particular workaround. I highly recommend watching the
videos from Google I/O and reading the articles to understand how filtering
and indexing works. This is a pretty good place to start:
http://code.google.com/appengine/articles/datastore/overview.html
On Fri, Dec 18, 2009 at 10:12 PM, Bombay Goose bombaygo...@gmail.comwrote:
Thanks DataNucleus team and Toby.
Sorry, but I have some more questions
1. How do I delete a particular table dynamically? would just unloading
the class do it? Iin that case, what if there are changes to the dynamic
table, i.e. column addition/dropping, wouldnt that require unloading the
class and hence deletion of table?
2. I am going through the Queries and Indexes section in the documentation
at
http://code.google.com/appengine/docs/java/datastore/queriesandindexes.html
This section says that inequality operators are allowed only one
property. Is anybody handling a situation where there are multiple
properties with inequality operators? If yes, how have you done it?
Thanks
On Wed, Dec 16, 2009 at 12:18 PM, Toby Reyelts to...@google.comwrote:
One other thing you might consider is using the native App Engine
datastore, since it's already schemaless. You can even mix and match using
the native API and JDO/JPA.
On Wed, Dec 16, 2009 at 1:30 AM, Bombay Goose
bombaygo...@gmail.comwrote:
Hello All,
I am doing a feasibility study of whether we can develop our application
on appengine or not.
Our application has a requirement where we have to create tables
dynamically, without restarting the application.
Is that possible in Appengine?
Datanucleus supports this through JDO, with some byte code
instrumentation. More info -
http://www.jpox.org/servlet/wiki/pages/viewpage.action?pageId=6619188
Is it possible through JPA? if yes, does appengine allow it?
if not, does Appengine allow Bytecode instrumentation so that we
can create classes dynamically according to the link above using JDO.
Any help is greatly appreciated.
Thanks,
G
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