In book it is a recommended way to iterate over sql results:
http://web2py.com/books/default/chapter/29/6
You can do all the steps in one statement:
1.
2.
3.
>>> for row in db(db.person.name=='Alex').select():
print row.name
Alex
2012. május 10., csütörtök 20:42:22 UTC+2 időpontban Bruce Wade a
következőt írta:
>
> Sorry, you really need to read more about how python works. If you learn
> how for loops work and memory you will understand the problem.
>
> One solution do the query before the for loop then loop through the
> objects. This may help at bit. Research xrange vs range
>
>
> On Thu, May 10, 2012 at 11:30 AM, szimszon <[email protected]> wrote:
>
>> Sorry I don't understand. What do you mean "achieve with join"?
>>
>> There is an empty for loop with db.executesql() without join. And it is
>> eating up the memory. :(
>>
>> 2012. május 10., csütörtök 19:12:30 UTC+2 időpontban Richard a következőt
>> írta:
>>
>>> You can't manage what you want to achieve with join?
>>>
>>> Richard
>>>
>>> On Thu, May 10, 2012 at 10:48 AM, szimszon <[email protected]> wrote:
>>>
>>>> Sorry for my dumbness but if something is wrong with my code please
>>>> point me the right line. I'm not so good in English if it comes to "object
>>>> instance count" and so. Yeah I know I should go and do some milkmaid job
>>>> :)
>>>> but I'm curious.
>>>>
>>>> I'm just define some variable:
>>>>
>>>> lista = list()
>>>> last_row = None
>>>> next_page_number = 0
>>>>
>>>> Go in a for loop that just assign the db query result one-by-one to row
>>>> variable.
>>>>
>>>> After that I assign the TABLE() helper to a list variable. That is it.
>>>>
>>>>
>>>>
>>>> 2012. május 10., csütörtök 16:34:49 UTC+2 időpontban Bruce Wade a
>>>> következőt írta:
>>>>
>>>>> Using direct sql query or DAL is going to cause the exact same problem
>>>>> in this situation.
>>>>>
>>>>> On Thu, May 10, 2012 at 7:28 AM, szimszon <[email protected]> wrote:
>>>>>
>>>>>> It's postgres:// in a
>>>>>> Version 1.99.7 (2012-04-23 11:26:23) dev of web2py, and
>>>>>>
>>>>>> Python 2.7.3 (default, Apr 20 2012, 22:44:07)
>>>>>> [GCC 4.6.3] on linux2
>>>>>>
>>>>>> python-psycopg2 2.4.5-1
>>>>>>
>>>>>>
>>>>>> 2012. május 10., csütörtök 15:40:36 UTC+2 időpontban rochacbruno a
>>>>>> következőt írta:
>>>>>>
>>>>>>> Just for curiosity, what happens if you do it in pure sql?
>>>>>>>
>>>>>>>
>>>>>>> for row in db.executesql("**sele****ct * from file_properties where
>>>>>>> id > 0"):
>>>>>>>
>>>>>>> # do something
>>>>>>>
>>>>>>>
>>>>>>> Does it have a lower memory usage?
>>>>>>>
>>>>>>>
>>>>>>> On Thu, May 10, 2012 at 4:14 AM, Bruce Wade < <[email protected]>
>>>>>>> > wrote:
>>>>>>>
>>>>>>>> for row in db( db.file_**propert****ies.id > 0 ).select(
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>>
>>>>>>> Bruno Rocha
>>>>>>> [http://rochacbruno.com.br]
>>>>>>>
>>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> --
>>>>> Regards,
>>>>> Bruce Wade
>>>>> http://ca.linkedin.com/in/**bruc**elwade<http://ca.linkedin.com/in/brucelwade>
>>>>> http://www.wadecybertech.com
>>>>> http://www.fittraineronline.**co**m <http://www.fittraineronline.com>-
>>>>> Fitness Personal Trainers Online
>>>>> http://www.warplydesigned.com
>>>>>
>>>>>
>>>
>
>
> --
> --
> Regards,
> Bruce Wade
> http://ca.linkedin.com/in/brucelwade
> http://www.wadecybertech.com
> http://www.fittraineronline.com - Fitness Personal Trainers Online
> http://www.warplydesigned.com
>
>
