On Sun, Oct 12, 2008 at 6:30 AM, Roy Leban <[EMAIL PROTECTED]> wrote:
>
> On Aug 22, 9:55 am, "Marzia Niccolai" <[EMAIL PROTECTED]> wrote:
>> You can't query for the key, there is really no need.
>
> I disagree that there is no need. I have some code that deals with a
> wide variety of models. The name of the model is passed in, so I do
> not have the model object. I want to do a query like this:
>
> q = db.GqlQuery("SELECT * FROM %s WHERE KEY = :k" % tablename,
> k=key)
> or q = db.GqlQuery("SELECT * FROM %s WHERE :f = :v" % tablename,
> f=field, v=value) # f happens to be "key"
>
> but I can't. Yes, I can do this (and it's how I handled it):
>
> eval(tablename).get(key)
>
> but (a) this is considerably clunkier, (b) it throws errors instead of
> handling an invalid table or key gracefully with no results returned,
> and (c) it doesn't support the second case, where the field name is a
> parameter -- you have to special case if (field.lower()=="key")
A key is unique to your application's datastore (in fact it's unique
across everyone's app), not just a particular model kind. You can just
do:
db.get(key)
That will return the entity, or None.
Dave.
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