Re: [sqlalchemy] Re: How can I use and_ and or_ in the orm query ?
we have this exact usage described right in the ORM tutorial: http://docs.sqlalchemy.org/en/rel_0_7/orm/tutorial.html#common-filter-operators On May 11, 2012, at 5:55 AM, Jonathan Vanasco wrote: Dan Kuebrich messaged me off-list -- the filter() method seems to accept the output of and_ or_ it would be great if the docs in each section referenced this. On May 10, 5:19 pm, Jonathan Vanasco jonat...@findmeon.com wrote: they're in the sql.expression , and the orm.query object doesn't have those methods. what query method do i use to integrate them ? -- 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 sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en. -- 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 sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
[sqlalchemy] How should I do inheritance using DeclarativeReflectedBase?
Even though the latest version of the DeclarativeRefletive example
includes some handling for inheritance, I still can not get it to
work. I try doing (mostly modified example from
https://bitbucket.org/sqlalchemy/sqlalchemy/src/408388e5faf4/examples/declarative_reflection/declarative_reflection.py):
from sqlalchemy.types import Integer
from sqlalchemy.types import String
from sqlalchemy.schema import ForeignKey
from sqlalchemy.schema import Column
from sqlalchemy.schema import Table
from sqlalchemy.orm import mapper
from sqlalchemy.orm.session import Session
from sqlalchemy.orm.util import _is_mapped_class
from sqlalchemy.engine import create_engine
from sqlalchemy.ext.declarative import declarative_base
class DeclarativeReflectedBase(object):
_mapper_args = []
@classmethod
def __mapper_cls__(cls, *args, **kw):
Declarative will use this function in lieu of
calling mapper() directly.
Collect each series of arguments and invoke
them when prepare() is called.
cls._mapper_args.append((args, kw))
@classmethod
def prepare(cls, engine):
Reflect all the tables and map !
while cls._mapper_args:
args, kw = cls._mapper_args.pop()
klass = args[0]
# autoload Table, which is already
# present in the metadata. This
# will fill in db-loaded columns
# into the existing Table object.
if args[1] is not None:
table = args[1]
Table(table.name,
cls.metadata,
extend_existing=True,
autoload_replace=False,
autoload=True,
autoload_with=engine,
schema=table.schema)
# see if we need 'inherits' in the
# mapper args. Declarative will have
# skipped this since mappings weren't
# available yet.
for c in klass.__bases__:
if _is_mapped_class(c):
kw['inherits'] = c
break
klass.__mapper__ = mapper(*args, **kw)
if __name__ == '__main__':
Base = declarative_base()
# create a separate base so that we can
# define a subset of classes as Reflected,
# instead of everything.
class Reflected(DeclarativeReflectedBase, Base):
__abstract__ = True
class Foo(Reflected):
__tablename__ = 'foo'
type_ = Column('type', String(32))
__mapper_args__ = {'polymorphic_on': type_,
'polymorphic_identity': 'foo'}
class Bar(Foo):
__tablename__ = 'bar'
__mapper_args__ = {'polymorphic_identity': 'bar'}
id = Column(Integer, ForeignKey('foo.id'), primary_key=True)
e = create_engine('sqlite://', echo=True)
e.execute(
create table foo(
id integer primary key,
type varchar(32),
data varchar(30)
)
)
e.execute(
create table bar(
id integer primary key,
bar_data varchar(30)
)
)
Reflected.prepare(e)
s = Session(e)
s.add_all([
Bar(data='d1', bar_data='b1'),
Bar(data='d2', bar_data='b2'),
Bar(data='d3', bar_data='b3'),
Foo(data='d4')
])
s.commit()
for f in s.query(Foo):
print f.data, getattr(f, 'bar_data', 'not_a_bar')
and sqlalchemy tries to find the type column in the table 'bar'. Am I
doing the inheritance set up wrong or is it some bug in
DeclarativeReflectiveBase?
Ignas
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Re: [sqlalchemy] Mapper compilation errors in multi threaded web application using dynamic mapping to selects
(Sorry if this message appears twice in the list - I first sent it using an unregistered mail address.) Hello, thank you for your quick reply. is there a problem in mapping classes to selects ([1]) /within a function/? with multiple threads, where the mappers initialization may first proceed as the product of a thread running, yes. you'd want to upgrade to 0.7 for the best versions of these fixes, or at least 0.6. If you must stay on 0.5, make sure all modules are fully imported, then run compile_mappers() before starting any threads. I tried this first as migrating to version 0.7 or 0.6 sounds like a significant (and currently unplanned) effort, so I hoped we could stay with 0.5 for the moment. So I identified our standard mapper calls to tables. It turned out they are invoked by a single function running in the startup phase, so I added a call to compile_mappers() at the end of this function. The function is invoked very early and even before the __init__() method of the WSGI application object - I hope this is early enough. Looking at the server logs one can see it is called right after server startup, as often as initial processes are configured. Unfortunately, there are still errors displayed. Most of the time I found 'Mapper' object has no attribute '_props'. I also tried to use the standard SQLAlchemy mapper() function instead of our wrapper mentioned in my first message (a variant of [1]). In most cases the system complained about the _props attribute as before, in rare cases the message dictionary changed size during iteration appeared. (I switched back to the standard mapper to find out if our wrapper could have an influence.) Am I correct that the results indicate we *have* to switch to 0.6/0.7 for a solution, or did I oversee something? From your message: If you must stay on 0.5, make sure all modules are fully imported, then run compile_mappers() before starting any threads. Could it be I am not loading enough modules? Does all modules mean all modules of the application, or all modules to map successfully? Thanks and regards Jochen Reference: [1] http://www.sqlalchemy.org/trac/wiki/UsageRecipes/SessionAwareMapper -- 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 sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
Re: [sqlalchemy] How should I do inheritance using DeclarativeReflectedBase?
On May 11, 2012, at 1:16 PM, Ignas Mikalajunas wrote: Even though the latest version of the DeclarativeRefletive example includes some handling for inheritance, I still can not get it to work. I try doing (mostly modified example from https://bitbucket.org/sqlalchemy/sqlalchemy/src/408388e5faf4/examples/declarative_reflection/declarative_reflection.py): and sqlalchemy tries to find the type column in the table 'bar'. Am I doing the inheritance set up wrong or is it some bug in DeclarativeReflectiveBase? would need to spend some time with it, the declarativereflective example hasn't been worked out for setting up an inheritance relationship as of yet. So there could be any number of issues with it (part of why it's only an example and not a real feature).. -- 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 sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
Re: [sqlalchemy] Mapper compilation errors in multi threaded web application using dynamic mapping to selects
On May 11, 2012, at 1:31 PM, Jochen Stenzel wrote: (Sorry if this message appears twice in the list - I first sent it using an unregistered mail address.) Hello, thank you for your quick reply. is there a problem in mapping classes to selects ([1]) /within a function/? with multiple threads, where the mappers initialization may first proceed as the product of a thread running, yes. you'd want to upgrade to 0.7 for the best versions of these fixes, or at least 0.6. If you must stay on 0.5, make sure all modules are fully imported, then run compile_mappers() before starting any threads. I tried this first as migrating to version 0.7 or 0.6 sounds like a significant (and currently unplanned) effort, so I hoped we could stay with 0.5 for the moment. So I identified our standard mapper calls to tables. It turned out they are invoked by a single function running in the startup phase, so I added a call to compile_mappers() at the end of this function. The function is invoked very early and even before the __init__() method of the WSGI application object - I hope this is early enough. Looking at the server logs one can see it is called right after server startup, as often as initial processes are configured. Unfortunately, there are still errors displayed. Most of the time I found 'Mapper' object has no attribute '_props'. I also tried to use the standard SQLAlchemy mapper() function instead of our wrapper mentioned in my first message (a variant of [1]). In most cases the system complained about the _props attribute as before, in rare cases the message dictionary changed size during iteration appeared. (I switched back to the standard mapper to find out if our wrapper could have an influence.) Am I correct that the results indicate we *have* to switch to 0.6/0.7 for a solution, or did I oversee something? From your message: If you must stay on 0.5, make sure all modules are fully imported, then run compile_mappers() before starting any threads. Could it be I am not loading enough modules? Does all modules mean all modules of the application, or all modules to map successfully? yes the issue is very likely that more modules are being imported within non-main threads, and more mappers are coming in. if you get absolutely every mapper loaded up, then call compile_mappers() before any threads spawn, this kind of problem shouldn't occur. There may be other bugs in mapper configuration in 0.5 though this seems quite unusual that you're getting threading errors this frequently (especially dictionary changed size ? stack trace on that ?) . Trying 0.6 at least might be worth it. -- 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 sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
Re: [sqlalchemy] Mapper compilation errors in multi threaded web application using dynamic mapping to selects
Could it be I am not loading enough modules? Does all modules mean all modules of the application, or all modules to map successfully? yes the issue is very likely that more modules are being imported within non-main threads, and more mappers are coming in. if you get absolutely every mapper loaded up, then call compile_mappers() before any threads spawn, this kind of problem shouldn't occur. Hm, should this include the dynamic mappers? These mappers are run with /request/ specific parameters - if a user requests to see data of a certain view, a select object (using the current view parameter value) and a related class are generated, used and released. These mappers /will/ come in with threads. So, if absolutely every mapper includes the mappers to selectables this cannot be achieved I fear ... Until now, I understood we should run all our standard mappers (to tables), finally run compile_mappers(), and could start the request handler cycle (with threaded handlers and new mappers produced on request) afterwards. There may be other bugs in mapper configuration in 0.5 though this seems quite unusual that you're getting threading errors this frequently (especially dictionary changed size ? stack trace on that ?) . I will try to produce a stack trace. (In the last instrumented debug versions, I caught all exceptions so the stack traces were not logged.) Trying 0.6 at least might be worth it. Just in case I could not describe clearly before how dynamic and request specific the function generated mappings are: would 0.6 allow us to use the pattern of dynamic mapping described above? Thanks and regards Jochen -- 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 sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
[sqlalchemy] Re: How can I use and_ and or_ in the orm query ?
it's not in the api docs though - which tends to come up first on the keyword search and is the more obvious place to look. http://docs.sqlalchemy.org/en/rel_0_7/orm/query.html#sqlalchemy.orm.query.Query.filter http://docs.sqlalchemy.org/en/rel_0_7/core/expression_api.html?highlight=and_#sqlalchemy.sql.expression.and_ http://docs.sqlalchemy.org/en/rel_0_7/core/expression_api.html?highlight=or_#sqlalchemy.sql.expression.or_ Just saying/linking something like: filter: This also accepts clauses created by the [and_] and [or_] functions. and_: or_: The result of this can also be used by the [filter] function. -- 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 sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
