why something not show the updated items ?

[张沈鹏(电子科大 毕/就业倒计时...)]

I write a web with pylons 0.97 dev beta3

use sqlalchemy4.5 with elixir

and the template system is moko

when I update the datebase then refresh the page

the updated items sometimes show and sometimes not

I think maybe the moko or sqlalchemy or elixir buffered the query result .

but how to solve this problem ?

thanks

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[Michael Bayer]

On Apr 5, 2008, at 12:19 AM, 张沈鹏(电子科大 毕/就业倒计
时...) wrote:

> I write a web with pylons 0.97 dev beta3
>
> use sqlalchemy4.5 with elixir
>
> and the template system is moko
>
> when I update the datebase then refresh the page
>
> the updated items sometimes show and sometimes not
>
> I think maybe the moko or sqlalchemy or elixir buffered the query
> result .
>
> but how to solve this problem ?
>

clear out your session - session.clear().

[张沈鹏(电子科大 毕/就业倒计时...)]

thanks for you answer :)

but I still have some problems

It's to say I should clear session manual once I update the database ?

can I set timeout somewhere to auto do this job ?

--

[Michael Bayer]

On Apr 5, 2008, at 1:13 PM, 张沈鹏(电子科大 毕/就业倒计
时...) wrote:

> thanks for you answer :)
>
> but I still have some problems
>
> It's to say I should clear session manual once I update the database ?
>
> can I set timeout somewhere to auto do this job ?
>

for a web application, you usually use a Session for the lifespan of a
request - at the end of the request, you close it out.

Pylons tutorial has an illustration of this pattern over at http://wiki.pylonshq.com/display/pylonsdocs/Using+SQLAlchemy+with+Pylons
. About halfway through, the example illustartes modifying the base
controller to say:

def __call__(self, environ, start_response):
try:
return WSGIController.__call__(self, environ, start_response)
finally:
meta.Session.remove()

SQLAlchemy 0.4.6 (likely version) will include an "auto-expire-on-
commit()" feature which will make this step unnecessary, if you use a
fully transactional Session.

[ZhangShen Peng(Uestc graduating...)]

I tried both remove and clear
but seems have no effect

I think maybe two reason:

1.elixir cached the query when I used Iike feed.posts ( OneToMany)
OR
2.mako cached the query result , because I did the feed.posts query in template

.................
A headache problem .

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[Michael Bayer]

On Apr 6, 2008, at 11:27 AM, ZhangShen Peng(Uestc graduating...) wrote:

> I tried both remove and clear
> but seems have no effect
>
> I think maybe two reason:
>
> 1.elixir cached the query when I used Iike feed.posts ( OneToMany)

mmm I dont think elixir is caching anything additional. However, if
you have a collection on an object, that is just a plain collection,
like a list - once its loaded, its loaded, unless you say
session.expire(object, ['collectionname']).

An alternative is to use a "Dynamic" relation, which will issue the
SQL to the database on each access (but still will return objects
cached in the Session if already found): http://www.sqlalchemy.org/docs/04/mappers.html#advdatamapping_relation_largecollections_dynamic

> 2.mako cached the query result , because I did the feed.posts query
> in template

only if you are using Mako cache options explicitly - nothing caches
by default.

[ZhangShen Peng(Uestc graduating...)]

now I use like this

class Feed(Entity):
has_property('posts',dynamic_loader(Post))

everything is ok !

My english is pool , so I don't know how to express the appreciate for
your help .

I just want to say THANKS VERY VERY MUCH :)

--