SQL ALCHEMY instantly refresh
Christian Démolis
Sqlalchemy seems to work with a cache, i want to deal with it.
Nota : i use sqlalchemy in non transactional mode
Session = scoped_session(sessionmaker(autocommit=True, bind=engine))
Alexandre Conrad
> How can i force sqlalchemy to refresh an object when i did a
> session.query???
You may want look at this:
http://www.sqlalchemy.org/docs/05/session.html#refreshing-expiring
You may, as well, look at "expunging".
Alex
Christian Démolis
Tu es français je pense au vu de ton prénom.
Je continue donc en français.
En fait j'ai 25000 lignes de codes derrière moi et j'aimerai éviter d'avoir à ajouter tous les refresh ou les session.query().populate_existing() partout dans mon code
J'ai tenté en vain de surcharger la méthode query de sqlalchemy mais je n'ai pas réussi...
J'ai trouvé ce lien qui est intéressant mais je n'ai pas réussi à l'exploiter :
http://www.sqlalchemy.org/trac/wiki/UsageRecipes/PreFilteredQuery
Alexandre Conrad
2009/9/17 Christian Démolis <christia...@gmail.com>:
> Bonjour,
>
> Tu es français je pense au vu de ton prénom.
> Je continue donc en français.
Nice guess.
I understand it feels more comfortable writing in French rather than
in English, but many people are reading this list (or is only Mike
doing support? ;) ) and may be interested at the topic. And more eyes
and brains may answer your question. So please keep conversations on
this list to its native language - English. If you really want to
switch to a non-English language with someone particular, please
exchange off-list, but I believe you'll dramatically reduce your
chances of solving your problem.
So for the record, you were explaining that you have 25000 lines of
code and you'd like to avoid to add refresh or
session.query().populate_existing() all around the place. You have
attempted to override the query method but couldn't make it. You have
pointed out the PreFilteredQuery
http://www.sqlalchemy.org/trac/wiki/UsageRecipes/PreFilteredQuery but
was unsuccessful achieving what you wanted.
Sorry, maybe someone else can help you there. I haven't played with
Query overriding myself.
Alex
Michael Bayer
def __init__(*arg, **kw):
self._populate_existing = True
super(MyQuery, self).__init__(*arg, **kw)
should do it....
>
> Alex
>
> >
>
Christian Démolis
Thx for the answer, thx to Alexandre to translate my mail.
Sorry, i continue in english, i tried to do that at the end of my declaration file :
Base.metadata.create_all(engine)
import sqlalchemy.orm.query
class MyQuery(sqlalchemy.orm.query.Query):
def __init__(*arg, **kw):
self._populate_existing = True
super(MyQuery, self).__init__(*arg, **kw)
session = Session()
print "Le temps de déclaration SQL ALCHEMY", time.time()-xref
Is it correct? i m not very good in subclassing :S
It seems to not work.
When i add a print in the __init__, i never see it during the execution of my program so MyQuery is not used i think.
Can u tell me where should i subclass Query? In the declaration.py? in module sqlalchemy?
I tried to add myquery here
Session = scoped_session(sessionmaker(autocommit=True, bind=engine, query_cls=MyQuery))
but it does error
File "C:\Python25\lib\site-packages\sqlalchemy-0.5.6-py2.5.egg\sqlalchemy\orm\
session.py", line 899, in query
return self._query_cls(entities, self, **kwargs)
File "Z:\Declaration.py", line 1451, in __init__
self._populate_existing = True
NameError: global name 'self' is not defined
I can t touch to the sqlalchemy module because the interpreter and libraries are installed on multiple computers which execute one unique code on a shared network path.
So it's more easy to change my source code than sqlalchemy code...
i just want to change session.query behavior without change the code of sqlalchemy itself, please help me.
Alexandre Conrad
class MyQuery(sqlalchemy.orm.query.Query):
def __init__(self, *arg, **kw):
...
Alex
2009/9/18 Christian Démolis <christia...@gmail.com>:
Christian Démolis
I m so shameful
It works very well now.
I post the subclass complete if anyone need it in future
Base.metadata.create_all(engine)
import sqlalchemy.orm.query
from sqlalchemy.orm.query import Query
class Query(Query):
def __init__(self, *arg, **kw):
print "I pass here"
self._populate_existing = True
super(Query, self).__init__(*arg, **kw)
Session = scoped_session(sessionmaker(autocommit=True, bind=engine, query_cls=Query))
session = Session()
The new query class must be passed to the session call.
thx for all