On Fri, Apr 26, 2013 at 12:06 PM, Werner <werner.bru...@sfr.fr> wrote:
> On 26/04/2013 16:41, alonn wrote:
>>
>> so not to load too much into memory I should do something like:
>>
>> for i in session.query(someobject).filter(id>something)
>> print i
>>
>> I'm guessing the answer is no, because of the nature of sql, but I'm not
>> an expert so I'm asking.
>
> yes you can, check out the doc for querying, e.g. the following if you use
> the ORM.
>
> http://sqlalchemy.readthedocs.org/en/rel_0_8/orm/tutorial.html#querying
Not entirely, if you don't use yield_per (as shown in the docs in
fact, but worth mentioning).
Seeing query:
if self._yield_per:
fetch = cursor.fetchmany(self._yield_per)
if not fetch:
break
else:
fetch = cursor.fetchall()
Not only that, but also all rows are processed and saved to a local
list, so all instances are built and populated way before you get the
first row. That is, unless you specify yield_per.
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