On Aug 2, 2011, at 11:31 AM, RVince wrote:
> Michael,
>
> Right, thats a better idea -- I am working with snippets of other
> people's code here. However, I still have the original problem of
> going from a ResultProxy object to output in a mako file which is a
> chasm I cannnot seem to bridge! RVInce
there's nothing wrong with assigning a ResultProxy to c.result, then iterating
it in a template, as long as the connection context remains open. Your
premature closing it is the likely issue here.
>
> On Aug 2, 10:06 am, Michael Bayer <mike...@zzzcomputing.com> wrote:
>> On Aug 2, 2011, at 9:07 AM, RVince wrote:
>>
>>> In my controller class, I perform a rather basic, straightforward SQL
>>> query:
>>
>>> connection = engine.connect()
>>
>> connection, OK
>>
>>> trans = connection.begin()
>>
>> start a transaction, OK
>>
>>> try:
>>> c.result = connection.execute("select
>>> current_disposition_code,count(*) as num from cms_input_file group by
>>> current_disposition_code;")
>>> connection.close()
>>
>> close the connection ? what happened to trans, wheres the rollback or
>> commit ? what about your c.result that hasn't been iterated yet ? both of
>> these need an active Connection to proceed correctly. Technically the
>> transaction is fine with just the connection.close() at the end but its a
>> strange form that doesn't make the intent clear. The cursor referenced by
>> the ResultProxy definitely should have exclusive access to its parent
>> Connection for its whole lifespan, though, closing it out can have one of
>> several negative effects, depending on the backend and the configuration of
>> the connection pool.
>>
>> Want to know what would be easy here ?
>>
>> c.result = engine.execute("select * from my_table")
>>
>> then you're done. The ResultProxy in this case manages the Connection
>> itself which will be closed when the ResultProxy closes. However this
>> assumes you just need one SQL statement in a transaction, it seems that
>> perhaps the begin() call is because you're doing several things with the one
>> Connection.
>>
>> Ideally, assuming this is Pylons, you'd have a single Connection declared
>> for all controllers up in your BaseController, with a trans =
>> connection.begin() at the top and trans.rollback() at the bottom. That way
>> the mechanics of providing database context to controllers is handled in
>> application logic and not business logic. Or you'd have the ORM Session
>> in place and just use Session.execute() to get a result.
>
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