[sqlalchemy] Failures with AssociationProxy (starting with r2598)
Starting with r2598, I'm seeing some failures with how I'm using the
association proxy. I've modified the
examples/association/proxied_association.py file which duplicates the
problem.
It is possible that I'm not suppose to remove associations like I am.
But it did work before (in 0.3.7 and 0.3.6).
It looks like if I read in part of the association into the current
session and then delete it, things don't go so well.
Index: examples/association/proxied_association.py
===
--- examples/association/proxied_association.py (revision 2723)
+++ examples/association/proxied_association.py (working copy)
@@ -106,8 +106,18 @@
+# new additions to proxied_association.py
+#engine.echo = True
+new_item = Item('new item', 100)
+session.clear()
+order = session.query(Order).get_by(customer_name='john smith')
+bogus = order.items[0].item_id # comment out and it works on 0.3.8
+order.itemassociations = None
+session.flush()
+order.items.append(new_item)
+session.flush()
It fails with:
sqlalchemy.exceptions.SQLError: (IntegrityError) orderitems.order_id
may not be NULL u'INSERT INTO orderitems (item_id, price) VALUES (?,
?)' [5, 100]
Thanks,
Paul
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[sqlalchemy] assign_mapper patch
Hi, I've modified assign_mapper so that it won't monkey patch methods which already exist on a mapped class. Whether this is correct behaviour or not probably depends on ones point of view... but I thought I'd submit the patch for consideration anyway. http://www.sqlalchemy.org/trac/attachment/ticket/596/assignmapper.diff -Sw. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: [MySQL] Checking if commit() is available
On Jun 11, 2007, at 6:46 PM, Monty Taylor wrote: > > Um - transactions have happily been there since 3.23.15. :) > > So the "best" way to do this is to check the db version and see if > it's > greater than 3.23.15 or not. > > "show variables like 'version'" will do the trick to get you the > version. If it's later than 3.23.15 you should be fine. > how about rollback() ? we have a note that it fails if you arent using InnoDB tables. of course this is something that should be addressed by MySQLDB. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] PYTZ and SA
Hello, I was having some issues using pytz (python timezone definitions) with sqlalchemy. Before I post the specifics of my problem, I'm curious if there is any documentation on this kind of thing or If anyone else here had tried it before. Thanks, Michael Carter --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: [MySQL] Checking if commit() is available
Michael Bayer wrote: > > On Jun 8, 2007, at 2:17 PM, Andreas Jung wrote: > >> >> --On 8. Juni 2007 14:05:39 -0400 Rick Morrison >> <[EMAIL PROTECTED]> wrote: >> >>> try: >>> t.commit() >>> except: >>> print 'Holy cow, this database is lame' >>> >>> >> This code is also lame :-) The code should work >> for arbitrary DSNs and swallowing an exception while >> committing is evil, evil, evil. > > with a pre-5 version of mysql, it is the lesser evil Um - transactions have happily been there since 3.23.15. :) So the "best" way to do this is to check the db version and see if it's greater than 3.23.15 or not. "show variables like 'version'" will do the trick to get you the version. If it's later than 3.23.15 you should be fine. Monty --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: multiple mappers on une table problem.
On Jun 11, 2007, at 12:21 PM, Glauco wrote:
> For this reason i've inserted explicit primaryjoin condition, and
> these condition work perfectly in the primary mapper.
> But in the secondary wont work...
>
theres many reasons why you probably dont want to do what youre
trying to do.
first off, adding relations to a non-primary mapper: the class still
will lazy load relationships from the primary mapper, since they are
invoked from attributes. it doesnt entirely make sense to add
relationships to a secondary mapper for this reason - the
relationships will only take effect from the secondary mapper if you
are using eager loading. and in that case, we dont really have any
test cases for that so i cant say how well its going to work.
secondly: a non-primary mapper is just an awkward way of defining an
ORM query. Since we support generative queries now, you can just
make a Query object with the criterion youre looking for and just
hold onto it...youre just adding a single WHERE criterion, so
my_secondary_query = query(MyClass).filter(table.c.tipo=='p'). much
easier. ideally Query should be replacing 90% of all non_primary
mapper use cases.
thirdly: it doesnt make much sense to use assign_mapper() with a
secondary mapper, since thats not the mapper which the class is
primarily associated with.
So after all that, if you still want to get it to work, you need the
primaryjoin criterion to be against the mapped selectable:
myselect = select[mytable]).alias('myselect')
mapper(MyClass, myselect, non_primary=True, properties={
'stuff': relation(OtherClass,
primaryjoin=myselect.c.id==othertable.c.myid)
})
you also may need to add the foreign_keys=[] parameter which
will identfify which columns in the join conditions are "foreign", if
SA cannot figure out what they are.
mapper(MyClass, myselect, non_primary=True, properties={
'stuff': relation(OtherClass,
primaryjoin=myselect.c.id==othertable.c.myid, foreign_keys=
[othertable.c.myid])
})
hope this helps...good luck
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[sqlalchemy] Re: SQLError.... label Error
On Jun 11, 2007, at 12:14 PM, Glauco wrote:
> my problem is exactly this... i don't use aliases, and the example
> is a qru constructed by SA.
you can only order by tables that you have added to the query
explicitly or via join(). you cant order by columns that are added
by eager loading.
i.e.
Operatore.join('somerelation').order_by(relatedtable.c.name).list()
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[sqlalchemy] Re: multiple mappers on une table problem.
Michael Bayer ha scritto:
> On Jun 11, 2007, at 11:12 AM, Glauco wrote:
>
>
>> This cause a lot of inspiegable problem to property that are perfecly
>> functional in the primary
>> sqlalchemy.exceptions.ArgumentError: Can't determine relation
>> direction
>> for relationship 'Blabla.comune_nascita (Comune)' - foreign key
>> columns
>> are present in neither the parent nor the child's mapped tables
>>
>>
>
> you need to explicitly specify conditions like primaryjoin,
> foreign_keys, etc.
>
> http://www.sqlalchemy.org/docs/
> adv_datamapping.html#advdatamapping_properties_customjoin
>
>
For this reason i've inserted explicit primaryjoin condition, and these
condition work perfectly in the primary mapper.
But in the secondary wont work...
class Anagrafica:
bla bla
# my primary mapper
assign_mapper(context,
Anagrafica,
tbl['anagrafica'],
column_prefix = 'anagrafica_',
extension = SelectResultsExt(),
properties = {
'comune' : relation( Comune,
primaryjoin = tbl['anagrafica'].c.id_comune ==
tbl['comune'].c.id ),
'nazione': relation( Nazione,
primaryjoin = tbl['anagrafica'].c.cod_nazionalita ==
tbl['nazione'].c.codice ),?
'comune_nascita' : relation( Comune,
primaryjoin = tbl['anagrafica'].c.id_comune_nascita
== tbl['comune'].c.id),
'nazione_nascita' : relation(Nazione,
primaryjoin = tbl['anagrafica'].c.cod_nazione_nascita
== tbl['nazione'].c.codice ),
'professione': relation( Professione ),
'titolo_studio' : relation( TitoloStudio ),
})
# my secondary mapper
class Person( Anagrafica ):
pass
assign_mapper(context,
Person,
select([tbl['anagrafica']], tbl['anagrafica'].c.tipo ==
'P').alias('person'),
column_prefix = 'anagrafica_',
extension = SelectResultsExt(),
non_primary = True,
properties = {
'comune' : relation( Comune,
primaryjoin = tbl['anagrafica'].c.id_comune ==
tbl['comune'].c.id ),
'nazione': relation( Nazione,
primaryjoin = tbl['anagrafica'].c.cod_nazionalita ==
tbl['nazione'].c.codice ),?
'comune_nascita' : relation( Comune,
primaryjoin = tbl['anagrafica'].c.id_comune_nascita
== tbl['comune'].c.id),
'nazione_nascita' : relation(Nazione,
primaryjoin = tbl['anagrafica'].c.cod_nazione_nascita
== tbl['nazione'].c.codice ),
'professione': relation( Professione ),
'titolo_studio' : relation( TitoloStudio ),
})
In [8]: Anagrafica.search()
Out[8]:
In [9]: Person.search()
ArgumentError: Can't determine relation direction for relationship
'Person.comune_nascita (Comune)' - foreign key columns are present in
neither the parent nor the child's mapped tables
Some ideas?
Thank you
Glauco
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[sqlalchemy] Re: SQLError.... label Error
Michael Bayer ha scritto:
> On Jun 11, 2007, at 11:19 AM, Glauco wrote:
>
>
>> I use hardly the column prefix, so my query are always aliased.
>> this obviously cause a lot of problem whith the order_by clause
>> (that NOT use the same aliases)
>>
>>
>
> the approach here depends on how this query is being constructed. if
> you are using your own alias objects, insert the columns as
> referenced from the alias object itself into the order_by clause.
>
> alias = mytable.alias('foo')
> alias.select(order_by=[alias.c.bar])
>
>
>
my problem is exactly this... i don't use aliases, and the example is a
qru constructed by SA.
*Operatore.select_by().order_by( Anagrafica.c.nome).list()*
SQLError: (ProgrammingError) invalid reference to FROM-clause entry for
table "anagrafica"
HINT: Perhaps you meant to reference the table alias "anon_f3fb".
'SELECT operatore.data_inizio_attivita AS
operatore_data_inizio_attivita, operatore.password AS
operatore_password, operatore.logname AS operatore_logname,
operatore.id_anagrafica AS operatore_id_anagrafica,
anon_4877.ts_ultima_modifica AS anon_4877_ts_ultima_modifica,
anon_4877.id AS anon_4877_id, anon_4877.id_anagrafica AS
anon_4877_id_anagrafica, anon_4877.id_operatore AS
anon_4877_id_operatore, anon_4877.data_inizio AS anon_4877_data_inizio,
anon_4877.bdn_data_ultima_modifica AS
anon_4877_bdn_data_ultima_modifica, anon_4877.bdn_id AS
anon_4877_bdn_id, anon_4877.codice_struttura AS
anon_4877_codice_struttura, anon_4877.id_azienda AS
anon_4877_id_azienda, anon_4877.stato_record AS anon_4877_stato_record,
anon_4877.bdn_specie AS anon_4877_bdn_specie, anon_4877.id_precedente AS
anon_4877_id_precedente, anon_4877.bdn_flag_carne_latte AS
anon_4877_bdn_flag_carne_latte, anon_4877.data_fine AS
anon_4877_data_fine, operatore.id AS operatore_id, anon_a2d6.codice AS
anon_a2d6_codice, anon_a2d6.descrizione AS anon_a2d6_descrizione,
anon_a2d6.group_id AS anon_a2d6_group_id, operatore.data_fine_attivita
AS operatore_data_fine_attivita, operatore.zoperoles AS
operatore_zoperoles, anon_f3fb.cod_nazionalita AS
anon_f3fb_cod_nazionalita, anon_f3fb.id AS anon_f3fb_id,
anon_f3fb.id_comune AS anon_f3fb_id_comune, anon_f3fb.cod_professione AS
anon_f3fb_cod_professione, anon_f3fb.dato_fiscale AS
anon_f3fb_dato_fiscale, anon_f3fb.localita AS anon_f3fb_localita,
anon_f3fb.telefono AS anon_f3fb_telefono, anon_f3fb.email AS
anon_f3fb_email, anon_f3fb.nome AS anon_f3fb_nome, anon_f3fb.tipo AS
anon_f3fb_tipo, anon_f3fb.cod_titolo_studio AS
anon_f3fb_cod_titolo_studio, anon_f3fb.indirizzo AS anon_f3fb_indirizzo,
anon_f3fb.id_precedente AS anon_f3fb_id_precedente,
anon_f3fb.cod_nazione_nascita AS anon_f3fb_cod_nazione_nascita,
anon_f3fb.id_comune_nascita AS anon_f3fb_id_comune_nascita,
anon_f3fb.stato_record AS anon_f3fb_stato_record, anon_f3fb.id_operatore
AS anon_f3fb_id_operatore, anon_f3fb.cap AS anon_f3fb_cap,
anon_f3fb.ts_ultima_modifica AS anon_f3fb_ts_ultima_modifica,
anon_f3fb.data_nascita AS anon_f3fb_data_nascita \nFROM operatore LEFT
OUTER JOIN azienda_veterinario AS anon_28bf ON anon_28bf.id_veterinario
= operatore.id LEFT OUTER JOIN unita_aziendale AS anon_4877 ON
anon_4877.id = anon_28bf.id_unita_aziendale LEFT OUTER JOIN acl AS
anon_e91a ON operatore.id = anon_e91a.id_operatore LEFT OUTER JOIN ruolo
AS anon_a2d6 ON anon_a2d6.codice = anon_e91a.cod_ruolo LEFT OUTER JOIN
anagrafica AS anon_f3fb ON anon_f3fb.id = operatore.id_anagrafica ORDER
BY anagrafica.nome, anon_28bf.id, anon_e91a.id, anon_f3fb.id' {}
some ideas?
Glauco
--
++
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Sfera Carta Software(r) [EMAIL PROTECTED]
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[sqlalchemy] Re: multiple mappers on une table problem.
On Jun 11, 2007, at 11:12 AM, Glauco wrote: > > This cause a lot of inspiegable problem to property that are perfecly > functional in the primary > sqlalchemy.exceptions.ArgumentError: Can't determine relation > direction > for relationship 'Blabla.comune_nascita (Comune)' - foreign key > columns > are present in neither the parent nor the child's mapped tables > you need to explicitly specify conditions like primaryjoin, foreign_keys, etc. http://www.sqlalchemy.org/docs/ adv_datamapping.html#advdatamapping_properties_customjoin --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] Re: SQLError.... label Error
On Jun 11, 2007, at 11:19 AM, Glauco wrote:
> I use hardly the column prefix, so my query are always aliased.
> this obviously cause a lot of problem whith the order_by clause
> (that NOT use the same aliases)
>
the approach here depends on how this query is being constructed. if
you are using your own alias objects, insert the columns as
referenced from the alias object itself into the order_by clause.
alias = mytable.alias('foo')
alias.select(order_by=[alias.c.bar])
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[sqlalchemy] SQLError.... label Error
I use hardly the column prefix, so my query are always aliased. this obviously cause a lot of problem whith the order_by clause (that NOT use the same aliases) Is there some solution or mus wait for the new relase? This is a tipical Example ... the anagrafica.nome ORDER_BY column don't work bu SA know how to use correclty the alias... beacause the ProgrammingError is correct. SQLError: (ProgrammingError) invalid reference to FROM-clause entry for table "anagrafica" HINT: Perhaps you meant to reference the table alias "anon_f3fb". SELECT operatore.data_inizio_attivita AS operatore_data_inizio_attivita, operatore.password AS operatore_password, operatore.logname AS operatore_logname, operatore.id_anagrafica AS operatore_id_anagrafica, operatore.data_fine_attivita AS operatore_data_fine_attivita, operatore.zoperoles AS operatore_zoperoles, anon_4877.ts_ultima_modifica AS anon_4877_ts_ultima_modifica, anon_4877.id AS anon_4877_id, anon_4877.id_anagrafica AS anon_4877_id_anagrafica, anon_4877.id_operatore AS anon_4877_id_operatore, anon_4877.data_inizio AS anon_4877_data_inizio, anon_4877.bdn_data_ultima_modifica AS anon_4877_bdn_data_ultima_modifica, anon_4877.bdn_id AS anon_4877_bdn_id, anon_4877.codice_struttura AS anon_4877_codice_struttura, anon_4877.id_azienda AS anon_4877_id_azienda, anon_4877.stato_record AS anon_4877_stato_record, anon_4877.bdn_specie AS anon_4877_bdn_specie, anon_4877.id_precedente AS anon_4877_id_precedente, anon_4877.bdn_flag_carne_latte AS anon_4877_bdn_flag_carne_latte, anon_4877.data_fine AS anon_4877_data_fine, operatore.id AS operatore_id, anon_a2d6.codice AS anon_a2d6_codice, anon_a2d6.descrizione AS anon_a2d6_descrizione, anon_a2d6.group_id AS anon_a2d6_group_id, anon_f3fb.cod_nazionalita AS anon_f3fb_cod_nazionalita, anon_f3fb.id AS anon_f3fb_id, anon_f3fb.id_comune AS anon_f3fb_id_comune, anon_f3fb.cod_professione AS anon_f3fb_cod_professione, anon_f3fb.dato_fiscale AS anon_f3fb_dato_fiscale, anon_f3fb.localita AS anon_f3fb_localita, anon_f3fb.telefono AS anon_f3fb_telefono, anon_f3fb.email AS anon_f3fb_email, anon_f3fb.nome AS anon_f3fb_nome, anon_f3fb.tipo AS anon_f3fb_tipo, anon_f3fb.cod_titolo_studio AS anon_f3fb_cod_titolo_studio, anon_f3fb.indirizzo AS anon_f3fb_indirizzo, anon_f3fb.id_precedente AS anon_f3fb_id_precedente, anon_f3fb.cod_nazione_nascita AS anon_f3fb_cod_nazione_nascita, anon_f3fb.id_comune_nascita AS anon_f3fb_id_comune_nascita, anon_f3fb.stato_record AS anon_f3fb_stato_record, anon_f3fb.id_operatore AS anon_f3fb_id_operatore, anon_f3fb.cap AS anon_f3fb_cap, anon_f3fb.ts_ultima_modifica AS anon_f3fb_ts_ultima_modifica, anon_f3fb.data_nascita AS anon_f3fb_data_nascita FROM operatore LEFT OUTER JOIN azienda_veterinario AS anon_28bf ON anon_28bf.id_veterinario = operatore.id LEFT OUTER JOIN unita_aziendale AS anon_4877 ON anon_4877.id = anon_28bf.id_unita_aziendale LEFT OUTER JOIN acl AS anon_e91a ON operatore.id = anon_e91a.id_operatore LEFT OUTER JOIN ruolo AS anon_a2d6 ON anon_a2d6.codice = anon_e91a.cod_ruolo LEFT OUTER JOIN anagrafica AS anon_f3fb ON anon_f3fb.id = operatore.id_anagrafica ORDER BY *_anagrafica.nome_*, anon_28bf.id, anon_e91a.id, anon_f3fb.id' -- ++ Glauco Uri - Programmatore glauco(at)allevatori.com Sfera Carta Software(r) [EMAIL PROTECTED] Via Bazzanese,69 Casalecchio di Reno(BO) - Tel. 051591054 ++ --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~--~~~~--~~--~--~---
[sqlalchemy] multiple mappers on une table problem.
Hi Folk, I'm finding difficult implement this features of SA .
The example is: a simple table with a column "type". I want to do a
secondary mapper based on the primary mapper with the only different in
the column type='something'
create table person(
name text,
type text);
class Person ( Obj ):
pass
assign_mapper(context,
Person,
tbl['person'],
column_prefix = 'person_',
extension = SelectResultsExt(),
properties = {
bla bla
})
class Blonde( Person ):
pass
assign_mapper(context,
Blonde,
select( [tbl['anagrafica']], tbl['anagrafica'].c.tipo ==
'P').alias('blonde'),
non_primary = True,
)
This cause a lot of inspiegable problem to property that are perfecly
functional in the primary
sqlalchemy.exceptions.ArgumentError: Can't determine relation direction
for relationship 'Blabla.comune_nascita (Comune)' - foreign key columns
are present in neither the parent nor the child's mapped tables
Some ideas?
Glauco
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Sfera Carta Software(r) [EMAIL PROTECTED]
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[sqlalchemy] Re: Problems trying to run a query - typeerror
SQLAlchemy doesnt expect your class to have customizations going on
with __new__(). either fix your __new__() method to require only
the cls argument, or create a MapperExtension that provides the
create_instance() method, so that you create new instances yourself:
http://www.sqlalchemy.org/docs/
adv_datamapping.html#advdatamapping_extending
On Jun 10, 2007, at 3:36 PM, nathan harmston wrote:
> HI,
>
> I m currently trying to build an api for a database and I really
> like the way that Djangos manager ( Class_name.objects ). This
> seems very intuitive for me. After reading through the some of the
> django source and getting slightly confused I ve implemented a
> basic version for one of my tables. The problem is I get an
> exception, when I m not expecting one. If this isnt a specific
> sqlalchemy question then please tell me so I can re-post to python
> etc.
>
> registry.py --> contains table definitions etc.
>
> Manager.py
>
> from Registry import *
>
> class Manager(object):
> def __init__(self, model, table=None):
> self.model = model
> self.table = table
> def get(self, slice):
> pass
> def all(self):
> print "1"
> mapper(self.model, interpro_table)
> print "2"
> session = create_session()
> print "3"
> query = session.query(self.model)
> print "4"
> return query.select()
>
> Models.py
>
> from Manager import *
>
> class ModelBase(type):
> def __new__(cls, name, bases, dict):
> print cls
> setattr(cls, 'objects', Manager(cls))
> return type.__new__(cls, name, bases, dict)
>
> class Model(object):
> __metaclass__=ModelBase
>
> class InterPro(Model):
> _tableName = interpro_table
> def __init__(self, interpro_ac):
> self.interpro_ac = interpro_ac
> def __str__(self):
> return "InterPro: %s" %(self.interpro_ac)
> def __repr__(self):
> return "InterPro: %s" %(self.interpro_ac)
>
> if __name__=='__main__':
> a = Manager(InterPro)
> print a
> print a.all() --> this prints out all of the objects in the
> database
> i = InterPro('IPR014697')
> print InterPro.objects
> print InterPro.objects.all()
> --> this fails and produces the exception.
>
> Traceback (most recent call last):
> File "Model.py ", line 28, in ?
> print InterPro.objects.all()
> File "/home/skeg/workspace/test/src/Manager.py", line 17, in all
> return query.select()
> File "/usr/lib/python2.4/site-packages/sqlalchemy/orm/query.py",
> line 247, in select
> return self.select_whereclause(whereclause=arg, **kwargs)
> File "/usr/lib/python2.4/site-packages/sqlalchemy/orm/query.py",
> line 252, in select_whereclause
> return self._select_statement(statement, params=params)
> File "/usr/lib/python2.4/site-packages/sqlalchemy/orm/query.py",
> line 378, in _select_statement
> return self.execute(statement, params=params, **kwargs)
> File "/usr/lib/python2.4/site-packages/sqlalchemy/orm/query.py",
> line 310, in execute
> return self.instances(result, **kwargs)
> File "/usr/lib/python2.4/site-packages/sqlalchemy/orm/query.py",
> line 329, in instances
> self.mapper._instance(context, row, result)
> File "/usr/lib/python2.4/site-packages/sqlalchemy/orm/mapper.py",
> line 1213, in _instance
> instance = self._create_instance(context.session)
> File "/usr/lib/python2.4/site-packages/sqlalchemy/orm/mapper.py",
> line 1234, in _create_instance
> obj = self.class_.__new__(self.class_)
> TypeError: __new__() takes exactly 4 arguments (1 given)
>
> Does anyone know what the problem is? Is it the way I ve programmed
> this using metaclasses or is it sqlalchemy and the way in
> instantiates objects or even both?
>
> Many Thanks in advance,
>
> Nathan
>
> >
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