Hi:
You can define the dao interfaces and write the implementation of
the interfaces with datastore low level api or some fast startup
framework other than JDO or JPA. If you need to migrate to other
platform which supports standard RDBMS, you implement the dao
interface with JDO, JPA or JDBC.
The entity relationship model design in appengine is very
different from other RDBMS. You can not use more than two inequality
filters or the 'OR' operator in your query. So the design which works
great with appengine is probably not good with RDBMS and vice versa. I
think even the model redesign is necessary when you leave appengine.
Unless you don't choose to use appengine, use JDO(JPA) save you
nothing.
On 6月12日, 上午1時07分, Mark Wyszomierski <mar...@gmail.com> wrote:
> Hmm ok I see, so I'm just using JDO without any frameworks on top of that,
> but as mentioned in the slim3 tests, JDO does add overhead (sometimes a
> significant amount). I don't plan to be doing any large queries (the slim3
> example fetches 10,000 objects which I don't plan on doing at any point),
> but what is important to me is that startup time. One to two seconds is
> fine, four seconds starts pushing it, anything above that is pretty bad.
>
> If we start using slim3 though, we lose the flexibility in moving to another
> host (not that I know of any that can compare to app engine) since it'll be
> interacting directly with big table instead of using jdo or jpa is an
> intermediate?
>
> Thanks
>
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