[sqlalchemy] Getting default value from python object

[sqlalchemy_mysql]

I understand default value is used to emit Insert statement. Is there any 
way to have default value is accessible via python object. See below example

>>> class User(Base):
... __tablename__ = 'users'
... id = Column(Integer, primary_key=True)
... name = Column(String)
... password = Column(String, default='welcome')
...
>>> ed_user = User(name='ed')
>>> print(ed_user.name)
ed
>>> print(ed_user.password)
None

Expect `print(ed_user.password)` to return 'welcome' in this case.

Adding it to a session, flush and query the object will return default 
value but is there a way to get default value without re-querying the 
object?


-- 
SQLAlchemy - 
The Python SQL Toolkit and Object Relational Mapper

http://www.sqlalchemy.org/

To post example code, please provide an MCVE: Minimal, Complete, and Verifiable 
Example.  See  http://stackoverflow.com/help/mcve for a full description.
--- 
You received this message because you are subscribed to the Google Groups 
"sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to sqlalchemy+unsubscr...@googlegroups.com.
To post to this group, send email to sqlalchemy@googlegroups.com.
Visit this group at https://groups.google.com/group/sqlalchemy.
For more options, visit https://groups.google.com/d/optout.

Re: [sqlalchemy] mapper existance checks possibly wrong

[Mike Bayer]

On Wed, Oct 25, 2017 at 9:25 AM, Антонио Антуан  wrote:
> As I said befire, sqlalchemy version: 1.0.19 and code is here:
> https://gist.github.com/aCLr/113ac292c05bdb01e964d8e9884d6e5f

I apologize, did not see that link.

Use the execute_and_instances() implemenation from
lib/sqlalchemy/orm/query.py, which means here use _bind_mapper():

def _execute_and_instances(self, querycontext):
self._check_bound_to_shard()
querycontext.attributes['shard_id'] = self._shard_id
result = self._connection_from_session(
mapper=self._bind_mapper(),
shard_id=self._shard_id).execute(
querycontext.statement,
self._params
)
return self.instances(result, querycontext)




>
> Currently I can't use another version. In that case, I think that here is
> the right decision:
> "Looks like I have to check if "_mapper_zero()" returns real mapper.
> Otherwise I should pass "None" to "_connection_from_session()" as value of
> "mapper" argument"
>
> Am I right?
>
>
> ср, 25 окт. 2017 г. в 16:18, Mike Bayer :
>>
>> On Wed, Oct 25, 2017 at 6:52 AM, Антонио Антуан 
>> wrote:
>> > Any news here?
>>
>> We would require a self-contained demonstration case that illustrates
>> your error as well as complete information on what specific SQLAlchemy
>> version you are targeting.  As mentioned in a different reply,
>> _mapper_zero has been fixed in 1.1 to always return a mapper.  I
>> would strongly advise targeting the 1.1 series for any new development
>> as that's where issues can still be fixed.
>>
>>
>>
>>
>>
>> >
>> > суббота, 21 октября 2017 г., 18:42:47 UTC+3 пользователь Антонио Антуан
>> > написал:
>> >>
>> >> I see that it is not happened when "bind" passed directly to
>> >> "sessionmaker"
>> >>
>> >> сб, 21 окт. 2017 г. в 18:33, Антонио Антуан :
>> >>>
>> >>>
>> >>>
>> >>> пятница, 20 октября 2017 г., 20:50:52 UTC+3 пользователь Mike Bayer
>> >>> написал:
>> 
>>  On Fri, Oct 20, 2017 at 11:05 AM, Simon King 
>>  wrote:
>>  > The "is not None" is important when checking a variable that may
>>  > contain a ClauseElement, precisely because ClauseElement defines
>>  > that
>>  > __bool__ method.
>>  >
>>  > However, in Session.get_bind(), "mapper" is not supposed to contain
>>  > a
>>  > ClauseElement. It should either be an instance of
>>  > sqlalchemy.orm.mapper.Mapper, or None, in which case "if mapper:"
>>  > is a
>>  > valid and concise way to write it. Comparing to None might be
>>  > strictly
>>  > more accurate, but it shouldn't be necessary.
>> 
>>  agree, "mapper" means "mapper" and it is not supposed to be a
>>  ClauseElement.   This sounds like arguments are not being passed
>>  correctly somewhere.   Would need a demonstration script if something
>>  in SQLAlchemy itself is claimed to be making the mistake.
>> >>>
>> >>>
>> >>> Ok, that code produces mentioned error:
>> >>> https://gist.github.com/aCLr/113ac292c05bdb01e964d8e9884d6e5f
>> >>> Traceback (most recent call last):
>> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 100, in
>> >>> 
>> >>> Session.query(with_recursive).set_shard('default').all()
>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
>> >>> 2654,
>> >>> in all
>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
>> >>> 2802,
>> >>> in __iter__
>> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 28, in
>> >>> _execute_and_instances
>> >>> shard_id=self._shard_id).execute(
>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
>> >>> 2806,
>> >>> in _connection_from_session
>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
>> >>> 984, in connection
>> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 40, in
>> >>> get_bind
>> >>> original_bind = super(RoutingSession, self).get_bind(mapper,
>> >>> clause)
>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
>> >>> 1336, in get_bind
>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/sql/elements.py", line
>> >>> 539, in __bool__
>> >>> TypeError: Boolean value of this clause is not defined
>> >>>
>> 
>>  >
>>  > Simon
>> 
>>  >
>>  >
>>  >
>>  > On Fri, Oct 20, 2017 at 3:17 PM, Антонио Антуан 
>>  > wrote:
>>  >> Really, `mapper` contains this: >  >> 0x7fe673fb0a50; group_getter>. But does it changes something? I
>>  >> already
>>  >> encountered this problem in my code, when I checked sqla-objects
>>  >> existance
>>  >> without "is not None", project was broken. Is it normal to omit
>>  >> that
>>  >> condition in sqlalchemy code?
>>  >>
>>  >> I use:
>>  > sqlalchemy.__version__
>>  >> '1.0.19'

Re: [sqlalchemy] mapper existance checks possibly wrong

[Антонио Антуан]

As I said befire, sqlalchemy version: 1.0.19 and code is here:
https://gist.github.com/aCLr/113ac292c05bdb01e964d8e9884d6e5f

Currently I can't use another version. In that case, I think that here is
the right decision:
"Looks like I have to check if "_mapper_zero()" returns real mapper.
Otherwise I should pass "None" to "_connection_from_session()" as value of
"mapper" argument"

Am I right?


ср, 25 окт. 2017 г. в 16:18, Mike Bayer :

> On Wed, Oct 25, 2017 at 6:52 AM, Антонио Антуан 
> wrote:
> > Any news here?
>
> We would require a self-contained demonstration case that illustrates
> your error as well as complete information on what specific SQLAlchemy
> version you are targeting.  As mentioned in a different reply,
> _mapper_zero has been fixed in 1.1 to always return a mapper.  I
> would strongly advise targeting the 1.1 series for any new development
> as that's where issues can still be fixed.
>
>
>
>
>
> >
> > суббота, 21 октября 2017 г., 18:42:47 UTC+3 пользователь Антонио Антуан
> > написал:
> >>
> >> I see that it is not happened when "bind" passed directly to
> >> "sessionmaker"
> >>
> >> сб, 21 окт. 2017 г. в 18:33, Антонио Антуан :
> >>>
> >>>
> >>>
> >>> пятница, 20 октября 2017 г., 20:50:52 UTC+3 пользователь Mike Bayer
> >>> написал:
> 
>  On Fri, Oct 20, 2017 at 11:05 AM, Simon King 
>  wrote:
>  > The "is not None" is important when checking a variable that may
>  > contain a ClauseElement, precisely because ClauseElement defines
> that
>  > __bool__ method.
>  >
>  > However, in Session.get_bind(), "mapper" is not supposed to contain
> a
>  > ClauseElement. It should either be an instance of
>  > sqlalchemy.orm.mapper.Mapper, or None, in which case "if mapper:"
> is a
>  > valid and concise way to write it. Comparing to None might be
> strictly
>  > more accurate, but it shouldn't be necessary.
> 
>  agree, "mapper" means "mapper" and it is not supposed to be a
>  ClauseElement.   This sounds like arguments are not being passed
>  correctly somewhere.   Would need a demonstration script if something
>  in SQLAlchemy itself is claimed to be making the mistake.
> >>>
> >>>
> >>> Ok, that code produces mentioned error:
> >>> https://gist.github.com/aCLr/113ac292c05bdb01e964d8e9884d6e5f
> >>> Traceback (most recent call last):
> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 100, in
> >>> 
> >>> Session.query(with_recursive).set_shard('default').all()
> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
> 2654,
> >>> in all
> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
> 2802,
> >>> in __iter__
> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 28, in
> >>> _execute_and_instances
> >>> shard_id=self._shard_id).execute(
> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
> 2806,
> >>> in _connection_from_session
> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
> >>> 984, in connection
> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 40, in
> >>> get_bind
> >>> original_bind = super(RoutingSession, self).get_bind(mapper,
> clause)
> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
> >>> 1336, in get_bind
> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/sql/elements.py", line
> >>> 539, in __bool__
> >>> TypeError: Boolean value of this clause is not defined
> >>>
> 
>  >
>  > Simon
> 
>  >
>  >
>  >
>  > On Fri, Oct 20, 2017 at 3:17 PM, Антонио Антуан 
>  > wrote:
>  >> Really, `mapper` contains this:   >> 0x7fe673fb0a50; group_getter>. But does it changes something? I
>  >> already
>  >> encountered this problem in my code, when I checked sqla-objects
>  >> existance
>  >> without "is not None", project was broken. Is it normal to omit
> that
>  >> condition in sqlalchemy code?
>  >>
>  >> I use:
>  > sqlalchemy.__version__
>  >> '1.0.19'
>  >>
>  >> пятница, 20 октября 2017 г., 16:42:23 UTC+3 пользователь Simon King
>  >> написал:
>  >>>
>  >>> On Fri, Oct 20, 2017 at 2:15 PM, Антонио Антуан <
> a.ch...@gmail.com>
>  >>> wrote:
>  >>> > Hi.
>  >>> > I use my own `RoutingSession` and `RoutingQuery` implementation,
>  >>> > most of
>  >>> > it
>  >>> > inspired by `sqlalchemy.ext.horizontal_shard`:
>  >>> >
>  >>> > class RoutingSession(Session):
>  >>> > def get_bind(self, mapper=None, clause=None, shard_id=None,
>  >>> > **kwargs):
>  >>> > original_bind = None
>  >>> > try:
>  >>> > original_bind = super(RoutingSession,
>  >>> > self).get_bind(mapper,
>  >>> > clause)
>  >>> > except UnboundExecutionError:
>  >>> >

Re: [sqlalchemy] mapper existance checks possibly wrong

[Mike Bayer]

On Wed, Oct 25, 2017 at 6:52 AM, Антонио Антуан  wrote:
> Any news here?

We would require a self-contained demonstration case that illustrates
your error as well as complete information on what specific SQLAlchemy
version you are targeting.  As mentioned in a different reply,
_mapper_zero has been fixed in 1.1 to always return a mapper.  I
would strongly advise targeting the 1.1 series for any new development
as that's where issues can still be fixed.





>
> суббота, 21 октября 2017 г., 18:42:47 UTC+3 пользователь Антонио Антуан
> написал:
>>
>> I see that it is not happened when "bind" passed directly to
>> "sessionmaker"
>>
>> сб, 21 окт. 2017 г. в 18:33, Антонио Антуан :
>>>
>>>
>>>
>>> пятница, 20 октября 2017 г., 20:50:52 UTC+3 пользователь Mike Bayer
>>> написал:

 On Fri, Oct 20, 2017 at 11:05 AM, Simon King 
 wrote:
 > The "is not None" is important when checking a variable that may
 > contain a ClauseElement, precisely because ClauseElement defines that
 > __bool__ method.
 >
 > However, in Session.get_bind(), "mapper" is not supposed to contain a
 > ClauseElement. It should either be an instance of
 > sqlalchemy.orm.mapper.Mapper, or None, in which case "if mapper:" is a
 > valid and concise way to write it. Comparing to None might be strictly
 > more accurate, but it shouldn't be necessary.

 agree, "mapper" means "mapper" and it is not supposed to be a
 ClauseElement.   This sounds like arguments are not being passed
 correctly somewhere.   Would need a demonstration script if something
 in SQLAlchemy itself is claimed to be making the mistake.
>>>
>>>
>>> Ok, that code produces mentioned error:
>>> https://gist.github.com/aCLr/113ac292c05bdb01e964d8e9884d6e5f
>>> Traceback (most recent call last):
>>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 100, in
>>> 
>>> Session.query(with_recursive).set_shard('default').all()
>>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line 2654,
>>> in all
>>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line 2802,
>>> in __iter__
>>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 28, in
>>> _execute_and_instances
>>> shard_id=self._shard_id).execute(
>>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line 2806,
>>> in _connection_from_session
>>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
>>> 984, in connection
>>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 40, in
>>> get_bind
>>> original_bind = super(RoutingSession, self).get_bind(mapper, clause)
>>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
>>> 1336, in get_bind
>>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/sql/elements.py", line
>>> 539, in __bool__
>>> TypeError: Boolean value of this clause is not defined
>>>

 >
 > Simon

 >
 >
 >
 > On Fri, Oct 20, 2017 at 3:17 PM, Антонио Антуан 
 > wrote:
 >> Really, `mapper` contains this: >>> >> 0x7fe673fb0a50; group_getter>. But does it changes something? I
 >> already
 >> encountered this problem in my code, when I checked sqla-objects
 >> existance
 >> without "is not None", project was broken. Is it normal to omit that
 >> condition in sqlalchemy code?
 >>
 >> I use:
 > sqlalchemy.__version__
 >> '1.0.19'
 >>
 >> пятница, 20 октября 2017 г., 16:42:23 UTC+3 пользователь Simon King
 >> написал:
 >>>
 >>> On Fri, Oct 20, 2017 at 2:15 PM, Антонио Антуан 
 >>> wrote:
 >>> > Hi.
 >>> > I use my own `RoutingSession` and `RoutingQuery` implementation,
 >>> > most of
 >>> > it
 >>> > inspired by `sqlalchemy.ext.horizontal_shard`:
 >>> >
 >>> > class RoutingSession(Session):
 >>> > def get_bind(self, mapper=None, clause=None, shard_id=None,
 >>> > **kwargs):
 >>> > original_bind = None
 >>> > try:
 >>> > original_bind = super(RoutingSession,
 >>> > self).get_bind(mapper,
 >>> > clause)
 >>> > except UnboundExecutionError:
 >>> > # may not be bound
 >>> > pass
 >>> > if shard_id is None:
 >>> > shard_id = TenantIDStorage.get_shard_id()  # just
 >>> > global
 >>> > storage
 >>> > bind_for_shard = self.__binds[shard_id]
 >>> > if original_bind is not None and original_bind.url ==
 >>> > bind_for_shard.url:
 >>> > return original_bind
 >>> > else:
 >>> > return bind_for_shard
 >>> >
 >>> > def __init__(self, shards=None, query_cls=CachingQuery,
 >>> > engines_factory=None, **kwargs):
 >>> > super(RoutingSession, self).__init__(query_cls=query_cls,
 >>> > **kwargs)
 

Re: [sqlalchemy] mapper existance checks possibly wrong

[Mike Bayer]

On Wed, Oct 25, 2017 at 8:02 AM, Антонио Антуан  wrote:
> Looks like I have to check if _mapper_zero() returns real mapper.

 _mapper_zero() in the 1.1 and 1.2 series will never return a
non-mapper (see https://bitbucket.org/zzzeek/sqlalchemy/issues/3608).
 I would strongly advise working with the 1.1. series at least as
1.0.x. is security patches only.



Otherwise
> I should pass None to "_connection_from_session()" as value of "mapper"
> argument. Right?
>
> ср, 25 окт. 2017 г. в 15:00, Антонио Антуан :
>>
>> As I mentioned before, "> group_getter>".
>>
>> ср, 25 окт. 2017 г. в 14:19, Simon King :
>>>
>>> What does self._mapper_zero() return in your
>>> RoutingQuery._execute_and_instances method?
>>>
>>> Simon
>>>
>>> On Wed, Oct 25, 2017 at 11:52 AM, Антонио Антуан 
>>> wrote:
>>> > Any news here?
>>> >
>>> > суббота, 21 октября 2017 г., 18:42:47 UTC+3 пользователь Антонио Антуан
>>> > написал:
>>> >>
>>> >> I see that it is not happened when "bind" passed directly to
>>> >> "sessionmaker"
>>> >>
>>> >> сб, 21 окт. 2017 г. в 18:33, Антонио Антуан :
>>> >>>
>>> >>>
>>> >>>
>>> >>> пятница, 20 октября 2017 г., 20:50:52 UTC+3 пользователь Mike Bayer
>>> >>> написал:
>>> 
>>>  On Fri, Oct 20, 2017 at 11:05 AM, Simon King
>>>  
>>>  wrote:
>>>  > The "is not None" is important when checking a variable that may
>>>  > contain a ClauseElement, precisely because ClauseElement defines
>>>  > that
>>>  > __bool__ method.
>>>  >
>>>  > However, in Session.get_bind(), "mapper" is not supposed to
>>>  > contain a
>>>  > ClauseElement. It should either be an instance of
>>>  > sqlalchemy.orm.mapper.Mapper, or None, in which case "if mapper:"
>>>  > is a
>>>  > valid and concise way to write it. Comparing to None might be
>>>  > strictly
>>>  > more accurate, but it shouldn't be necessary.
>>> 
>>>  agree, "mapper" means "mapper" and it is not supposed to be a
>>>  ClauseElement.   This sounds like arguments are not being passed
>>>  correctly somewhere.   Would need a demonstration script if
>>>  something
>>>  in SQLAlchemy itself is claimed to be making the mistake.
>>> >>>
>>> >>>
>>> >>> Ok, that code produces mentioned error:
>>> >>> https://gist.github.com/aCLr/113ac292c05bdb01e964d8e9884d6e5f
>>> >>> Traceback (most recent call last):
>>> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 100, in
>>> >>> 
>>> >>> Session.query(with_recursive).set_shard('default').all()
>>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
>>> >>> 2654,
>>> >>> in all
>>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
>>> >>> 2802,
>>> >>> in __iter__
>>> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 28, in
>>> >>> _execute_and_instances
>>> >>> shard_id=self._shard_id).execute(
>>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
>>> >>> 2806,
>>> >>> in _connection_from_session
>>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
>>> >>> 984, in connection
>>> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 40, in
>>> >>> get_bind
>>> >>> original_bind = super(RoutingSession, self).get_bind(mapper,
>>> >>> clause)
>>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
>>> >>> 1336, in get_bind
>>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/sql/elements.py",
>>> >>> line
>>> >>> 539, in __bool__
>>> >>> TypeError: Boolean value of this clause is not defined
>>> >>>
>>> 
>>>  >
>>>  > Simon
>>> 
>>>  >
>>>  >
>>>  >
>>>  > On Fri, Oct 20, 2017 at 3:17 PM, Антонио Антуан
>>>  > 
>>>  > wrote:
>>>  >> Really, `mapper` contains this: >>  >> 0x7fe673fb0a50; group_getter>. But does it changes something? I
>>>  >> already
>>>  >> encountered this problem in my code, when I checked sqla-objects
>>>  >> existance
>>>  >> without "is not None", project was broken. Is it normal to omit
>>>  >> that
>>>  >> condition in sqlalchemy code?
>>>  >>
>>>  >> I use:
>>>  > sqlalchemy.__version__
>>>  >> '1.0.19'
>>>  >>
>>>  >> пятница, 20 октября 2017 г., 16:42:23 UTC+3 пользователь Simon
>>>  >> King
>>>  >> написал:
>>>  >>>
>>>  >>> On Fri, Oct 20, 2017 at 2:15 PM, Антонио Антуан
>>>  >>> 
>>>  >>> wrote:
>>>  >>> > Hi.
>>>  >>> > I use my own `RoutingSession` and `RoutingQuery`
>>>  >>> > implementation,
>>>  >>> > most of
>>>  >>> > it
>>>  >>> > inspired by `sqlalchemy.ext.horizontal_shard`:
>>>  >>> >
>>>  >>> > class RoutingSession(Session):
>>>  >>> > def get_bind(self, mapper=None, clause=None,
>>>  >>> > shard_id=None,
>>>  >>> > 

Re: [sqlalchemy] sqlalchemy.select().group_by(expr) doesn't use label of expression, while .order_by(expr) does

[Mike Bayer]

On Wed, Oct 25, 2017 at 8:55 AM, Gijs Molenaar  wrote:
>
>
> Op vrijdag 20 oktober 2017 19:11:56 UTC+2 schreef Mike Bayer:
>>
>> On Thu, Oct 19, 2017 at 4:25 AM, Gijs Molenaar 
>> wrote:
>> >
>> >
>> > Op donderdag 19 oktober 2017 03:10:21 UTC+2 schreef Mike Bayer:
>> >>
>> >> On Wed, Oct 18, 2017 at 7:38 AM, Gijs Molenaar 
>> >> wrote:
>> >> > hi!
>> >> >
>> >> >
>> >> > Not sure if this a bug or something I should in my SQLAlchemy
>> >> > dialect,
>> >> > but
>> >> > currently
>> >> >
>> >> >
>> >> > expr = (table.c.x + table.c.y).label('lx')
>> >> > select([func.count(table.c.id), expr]).group_by(expr).order_by(expr)
>> >> >
>> >> > compiles to:
>> >> >
>> >> > SELECT count(some_table.id) AS count_1, some_table.x + some_table.y
>> >> > AS
>> >> > lx
>> >> > \nFROM some_table GROUP BY some_table.x + some_table.y ORDER BY lx;
>> >> >
>> >> >
>> >> > which works fine for for example sqlite, but MonetDB requires the use
>> >> > of
>> >> > the
>> >> > lx label in the GROUP BY, which I think makes sense? Should this be
>> >> > addressed on the SQLalchemy side or on the MonetDB dialect side?
>> >>
>> >> so this was overhauled in
>> >>
>> >>
>> >> http://docs.sqlalchemy.org/en/latest/changelog/migration_09.html#label-constructs-can-now-render-as-their-name-alone-in-an-order-by
>> >> where we changed ORDER BY to use the label name when the expression is
>> >> passed.
>> >>
>> >> so the immediate answer would be to not actually order by the label().
>> >
>> >
>> > I think i didn't formulate my e-mail correctly. The ORDER BY is not the
>> > problem, it is the GROUP BY that requires a label. If the GROUP BY
>> > doesn't
>> > use a label (just like ORDER BY), MonetDB doesn't want to eat the query.
>>
>> this is my fault because I read/reply to these emails very fast and
>> focus mainly on the code I see.If you want it the other way
>> around, there is the feature described at:
>>
>>
>> https://docs.sqlalchemy.org/en/latest/changelog/migration_10.html#order-by-and-group-by-are-special-cases
>>
>> that is, say group_by("somelabel").
>>
>> If you need this to be more automatic for this backend, we can look
>> into seeing how the "ORDER BY" version of the feature can be more
>> generalized on a backend-specific basis but this would be longer-term.
>>
>
> Hi Mike,
>
> My main concern is to get the test suite pass for now :) What you propose
> doesn't make the dialect work with the current test suite right?

I assume this is the single test test_group_by_composed, for the
immediate case you can override it in your local test_suite.py file.
 We can add an @exclusion for it too.

>
> greetings,
>
>  - Gijs
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> description.
> ---
> You received this message because you are subscribed to the Google Groups
> "sqlalchemy" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to sqlalchemy+unsubscr...@googlegroups.com.
>
> To post to this group, send email to sqlalchemy@googlegroups.com.
> Visit this group at https://groups.google.com/group/sqlalchemy.
> For more options, visit https://groups.google.com/d/optout.

-- 
SQLAlchemy - 
The Python SQL Toolkit and Object Relational Mapper

http://www.sqlalchemy.org/

To post example code, please provide an MCVE: Minimal, Complete, and Verifiable 
Example.  See  http://stackoverflow.com/help/mcve for a full description.
--- 
You received this message because you are subscribed to the Google Groups 
"sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to sqlalchemy+unsubscr...@googlegroups.com.
To post to this group, send email to sqlalchemy@googlegroups.com.
Visit this group at https://groups.google.com/group/sqlalchemy.
For more options, visit https://groups.google.com/d/optout.

Re: [sqlalchemy] sqlalchemy.select().group_by(expr) doesn't use label of expression, while .order_by(expr) does

[Gijs Molenaar]

Op vrijdag 20 oktober 2017 19:11:56 UTC+2 schreef Mike Bayer:
>
> On Thu, Oct 19, 2017 at 4:25 AM, Gijs Molenaar  > wrote: 
> > 
> > 
> > Op donderdag 19 oktober 2017 03:10:21 UTC+2 schreef Mike Bayer: 
> >> 
> >> On Wed, Oct 18, 2017 at 7:38 AM, Gijs Molenaar  
> >> wrote: 
> >> > hi! 
> >> > 
> >> > 
> >> > Not sure if this a bug or something I should in my SQLAlchemy 
> dialect, 
> >> > but 
> >> > currently 
> >> > 
> >> > 
> >> > expr = (table.c.x + table.c.y).label('lx') 
> >> > select([func.count(table.c.id), expr]).group_by(expr).order_by(expr) 
> >> > 
> >> > compiles to: 
> >> > 
> >> > SELECT count(some_table.id) AS count_1, some_table.x + some_table.y 
> AS 
> >> > lx 
> >> > \nFROM some_table GROUP BY some_table.x + some_table.y ORDER BY lx; 
> >> > 
> >> > 
> >> > which works fine for for example sqlite, but MonetDB requires the use 
> of 
> >> > the 
> >> > lx label in the GROUP BY, which I think makes sense? Should this be 
> >> > addressed on the SQLalchemy side or on the MonetDB dialect side? 
> >> 
> >> so this was overhauled in 
> >> 
> >> 
> http://docs.sqlalchemy.org/en/latest/changelog/migration_09.html#label-constructs-can-now-render-as-their-name-alone-in-an-order-by
>  
> >> where we changed ORDER BY to use the label name when the expression is 
> >> passed. 
> >> 
> >> so the immediate answer would be to not actually order by the label(). 
> > 
> > 
> > I think i didn't formulate my e-mail correctly. The ORDER BY is not the 
> > problem, it is the GROUP BY that requires a label. If the GROUP BY 
> doesn't 
> > use a label (just like ORDER BY), MonetDB doesn't want to eat the query. 
>
> this is my fault because I read/reply to these emails very fast and 
> focus mainly on the code I see.If you want it the other way 
> around, there is the feature described at: 
>
>
> https://docs.sqlalchemy.org/en/latest/changelog/migration_10.html#order-by-and-group-by-are-special-cases
>  
>
> that is, say group_by("somelabel"). 
>
> If you need this to be more automatic for this backend, we can look 
> into seeing how the "ORDER BY" version of the feature can be more 
> generalized on a backend-specific basis but this would be longer-term. 
>
>
Hi Mike,

My main concern is to get the test suite pass for now :) What you propose 
doesn't make the dialect work with the current test suite right?

greetings,

 - Gijs 

-- 
SQLAlchemy - 
The Python SQL Toolkit and Object Relational Mapper

http://www.sqlalchemy.org/

To post example code, please provide an MCVE: Minimal, Complete, and Verifiable 
Example.  See  http://stackoverflow.com/help/mcve for a full description.
--- 
You received this message because you are subscribed to the Google Groups 
"sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to sqlalchemy+unsubscr...@googlegroups.com.
To post to this group, send email to sqlalchemy@googlegroups.com.
Visit this group at https://groups.google.com/group/sqlalchemy.
For more options, visit https://groups.google.com/d/optout.

Re: [sqlalchemy] mapper existance checks possibly wrong

[Simon King]

This is complete guesswork - I haven't examined this code in detail so
I could be wrong. Also, I don't know what version of SQLAlchemy you
are using, so this may not apply.

Session.connection takes separate "mapper" and "clause" parameters:

https://bitbucket.org/zzzeek/sqlalchemy/src/f34b180ca9059a74c3bf1db1b79e187c3f4b81c9/lib/sqlalchemy/orm/session.py#session.py-958

Query._execute_and_instances passes both of those parameters:

https://bitbucket.org/zzzeek/sqlalchemy/src/f34b180ca9059a74c3bf1db1b79e187c3f4b81c9/lib/sqlalchemy/orm/query.py#query.py-2893

(via the _get_bind_args helper function)

Your overridden version of _execute_and_instances is passing a clause
in the "mapper" parameter, which seems wrong. Somehow you need to fix
that, perhaps by using the _get_bind_args helper.

Simon



On Wed, Oct 25, 2017 at 1:02 PM, Антонио Антуан  wrote:
> Looks like I have to check if _mapper_zero() returns real mapper. Otherwise
> I should pass None to "_connection_from_session()" as value of "mapper"
> argument. Right?
>
> ср, 25 окт. 2017 г. в 15:00, Антонио Антуан :
>>
>> As I mentioned before, "> group_getter>".
>>
>> ср, 25 окт. 2017 г. в 14:19, Simon King :
>>>
>>> What does self._mapper_zero() return in your
>>> RoutingQuery._execute_and_instances method?
>>>
>>> Simon
>>>
>>> On Wed, Oct 25, 2017 at 11:52 AM, Антонио Антуан 
>>> wrote:
>>> > Any news here?
>>> >
>>> > суббота, 21 октября 2017 г., 18:42:47 UTC+3 пользователь Антонио Антуан
>>> > написал:
>>> >>
>>> >> I see that it is not happened when "bind" passed directly to
>>> >> "sessionmaker"
>>> >>
>>> >> сб, 21 окт. 2017 г. в 18:33, Антонио Антуан :
>>> >>>
>>> >>>
>>> >>>
>>> >>> пятница, 20 октября 2017 г., 20:50:52 UTC+3 пользователь Mike Bayer
>>> >>> написал:
>>> 
>>>  On Fri, Oct 20, 2017 at 11:05 AM, Simon King
>>>  
>>>  wrote:
>>>  > The "is not None" is important when checking a variable that may
>>>  > contain a ClauseElement, precisely because ClauseElement defines
>>>  > that
>>>  > __bool__ method.
>>>  >
>>>  > However, in Session.get_bind(), "mapper" is not supposed to
>>>  > contain a
>>>  > ClauseElement. It should either be an instance of
>>>  > sqlalchemy.orm.mapper.Mapper, or None, in which case "if mapper:"
>>>  > is a
>>>  > valid and concise way to write it. Comparing to None might be
>>>  > strictly
>>>  > more accurate, but it shouldn't be necessary.
>>> 
>>>  agree, "mapper" means "mapper" and it is not supposed to be a
>>>  ClauseElement.   This sounds like arguments are not being passed
>>>  correctly somewhere.   Would need a demonstration script if
>>>  something
>>>  in SQLAlchemy itself is claimed to be making the mistake.
>>> >>>
>>> >>>
>>> >>> Ok, that code produces mentioned error:
>>> >>> https://gist.github.com/aCLr/113ac292c05bdb01e964d8e9884d6e5f
>>> >>> Traceback (most recent call last):
>>> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 100, in
>>> >>> 
>>> >>> Session.query(with_recursive).set_shard('default').all()
>>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
>>> >>> 2654,
>>> >>> in all
>>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
>>> >>> 2802,
>>> >>> in __iter__
>>> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 28, in
>>> >>> _execute_and_instances
>>> >>> shard_id=self._shard_id).execute(
>>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
>>> >>> 2806,
>>> >>> in _connection_from_session
>>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
>>> >>> 984, in connection
>>> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 40, in
>>> >>> get_bind
>>> >>> original_bind = super(RoutingSession, self).get_bind(mapper,
>>> >>> clause)
>>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
>>> >>> 1336, in get_bind
>>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/sql/elements.py",
>>> >>> line
>>> >>> 539, in __bool__
>>> >>> TypeError: Boolean value of this clause is not defined
>>> >>>
>>> 
>>>  >
>>>  > Simon
>>> 
>>>  >
>>>  >
>>>  >
>>>  > On Fri, Oct 20, 2017 at 3:17 PM, Антонио Антуан
>>>  > 
>>>  > wrote:
>>>  >> Really, `mapper` contains this: >>  >> 0x7fe673fb0a50; group_getter>. But does it changes something? I
>>>  >> already
>>>  >> encountered this problem in my code, when I checked sqla-objects
>>>  >> existance
>>>  >> without "is not None", project was broken. Is it normal to omit
>>>  >> that
>>>  >> condition in sqlalchemy code?
>>>  >>
>>>  >> I use:
>>>  > sqlalchemy.__version__
>>>  >> '1.0.19'
>>>  >>
>>>  >> пятница, 20 октября 2017 г., 16:42:23 UTC+3 

Re: [sqlalchemy] mapper existance checks possibly wrong

[Антонио Антуан]

Looks like I have to check if _mapper_zero() returns real mapper. Otherwise
I should pass None to "_connection_from_session()" as value of "mapper"
argument. Right?

ср, 25 окт. 2017 г. в 15:00, Антонио Антуан :

> As I mentioned before, " group_getter>".
>
> ср, 25 окт. 2017 г. в 14:19, Simon King :
>
>> What does self._mapper_zero() return in your
>> RoutingQuery._execute_and_instances method?
>>
>> Simon
>>
>> On Wed, Oct 25, 2017 at 11:52 AM, Антонио Антуан 
>> wrote:
>> > Any news here?
>> >
>> > суббота, 21 октября 2017 г., 18:42:47 UTC+3 пользователь Антонио Антуан
>> > написал:
>> >>
>> >> I see that it is not happened when "bind" passed directly to
>> >> "sessionmaker"
>> >>
>> >> сб, 21 окт. 2017 г. в 18:33, Антонио Антуан :
>> >>>
>> >>>
>> >>>
>> >>> пятница, 20 октября 2017 г., 20:50:52 UTC+3 пользователь Mike Bayer
>> >>> написал:
>> 
>>  On Fri, Oct 20, 2017 at 11:05 AM, Simon King > >
>>  wrote:
>>  > The "is not None" is important when checking a variable that may
>>  > contain a ClauseElement, precisely because ClauseElement defines
>> that
>>  > __bool__ method.
>>  >
>>  > However, in Session.get_bind(), "mapper" is not supposed to
>> contain a
>>  > ClauseElement. It should either be an instance of
>>  > sqlalchemy.orm.mapper.Mapper, or None, in which case "if mapper:"
>> is a
>>  > valid and concise way to write it. Comparing to None might be
>> strictly
>>  > more accurate, but it shouldn't be necessary.
>> 
>>  agree, "mapper" means "mapper" and it is not supposed to be a
>>  ClauseElement.   This sounds like arguments are not being passed
>>  correctly somewhere.   Would need a demonstration script if something
>>  in SQLAlchemy itself is claimed to be making the mistake.
>> >>>
>> >>>
>> >>> Ok, that code produces mentioned error:
>> >>> https://gist.github.com/aCLr/113ac292c05bdb01e964d8e9884d6e5f
>> >>> Traceback (most recent call last):
>> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 100, in
>> >>> 
>> >>> Session.query(with_recursive).set_shard('default').all()
>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
>> 2654,
>> >>> in all
>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
>> 2802,
>> >>> in __iter__
>> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 28, in
>> >>> _execute_and_instances
>> >>> shard_id=self._shard_id).execute(
>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
>> 2806,
>> >>> in _connection_from_session
>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
>> >>> 984, in connection
>> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 40, in
>> >>> get_bind
>> >>> original_bind = super(RoutingSession, self).get_bind(mapper,
>> clause)
>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
>> >>> 1336, in get_bind
>> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/sql/elements.py", line
>> >>> 539, in __bool__
>> >>> TypeError: Boolean value of this clause is not defined
>> >>>
>> 
>>  >
>>  > Simon
>> 
>>  >
>>  >
>>  >
>>  > On Fri, Oct 20, 2017 at 3:17 PM, Антонио Антуан > >
>>  > wrote:
>>  >> Really, `mapper` contains this: >  >> 0x7fe673fb0a50; group_getter>. But does it changes something? I
>>  >> already
>>  >> encountered this problem in my code, when I checked sqla-objects
>>  >> existance
>>  >> without "is not None", project was broken. Is it normal to omit
>> that
>>  >> condition in sqlalchemy code?
>>  >>
>>  >> I use:
>>  > sqlalchemy.__version__
>>  >> '1.0.19'
>>  >>
>>  >> пятница, 20 октября 2017 г., 16:42:23 UTC+3 пользователь Simon
>> King
>>  >> написал:
>>  >>>
>>  >>> On Fri, Oct 20, 2017 at 2:15 PM, Антонио Антуан <
>> a.ch...@gmail.com>
>>  >>> wrote:
>>  >>> > Hi.
>>  >>> > I use my own `RoutingSession` and `RoutingQuery`
>> implementation,
>>  >>> > most of
>>  >>> > it
>>  >>> > inspired by `sqlalchemy.ext.horizontal_shard`:
>>  >>> >
>>  >>> > class RoutingSession(Session):
>>  >>> > def get_bind(self, mapper=None, clause=None, shard_id=None,
>>  >>> > **kwargs):
>>  >>> > original_bind = None
>>  >>> > try:
>>  >>> > original_bind = super(RoutingSession,
>>  >>> > self).get_bind(mapper,
>>  >>> > clause)
>>  >>> > except UnboundExecutionError:
>>  >>> > # may not be bound
>>  >>> > pass
>>  >>> > if shard_id is None:
>>  >>> > shard_id = TenantIDStorage.get_shard_id()  # just
>>  >>> > global
>>  >>> > storage
>>  >>> > bind_for_shard = self.__binds[shard_id]
>>  

Re: [sqlalchemy] mapper existance checks possibly wrong

[Антонио Антуан]

As I mentioned before, "".

ср, 25 окт. 2017 г. в 14:19, Simon King :

> What does self._mapper_zero() return in your
> RoutingQuery._execute_and_instances method?
>
> Simon
>
> On Wed, Oct 25, 2017 at 11:52 AM, Антонио Антуан 
> wrote:
> > Any news here?
> >
> > суббота, 21 октября 2017 г., 18:42:47 UTC+3 пользователь Антонио Антуан
> > написал:
> >>
> >> I see that it is not happened when "bind" passed directly to
> >> "sessionmaker"
> >>
> >> сб, 21 окт. 2017 г. в 18:33, Антонио Антуан :
> >>>
> >>>
> >>>
> >>> пятница, 20 октября 2017 г., 20:50:52 UTC+3 пользователь Mike Bayer
> >>> написал:
> 
>  On Fri, Oct 20, 2017 at 11:05 AM, Simon King 
>  wrote:
>  > The "is not None" is important when checking a variable that may
>  > contain a ClauseElement, precisely because ClauseElement defines
> that
>  > __bool__ method.
>  >
>  > However, in Session.get_bind(), "mapper" is not supposed to contain
> a
>  > ClauseElement. It should either be an instance of
>  > sqlalchemy.orm.mapper.Mapper, or None, in which case "if mapper:"
> is a
>  > valid and concise way to write it. Comparing to None might be
> strictly
>  > more accurate, but it shouldn't be necessary.
> 
>  agree, "mapper" means "mapper" and it is not supposed to be a
>  ClauseElement.   This sounds like arguments are not being passed
>  correctly somewhere.   Would need a demonstration script if something
>  in SQLAlchemy itself is claimed to be making the mistake.
> >>>
> >>>
> >>> Ok, that code produces mentioned error:
> >>> https://gist.github.com/aCLr/113ac292c05bdb01e964d8e9884d6e5f
> >>> Traceback (most recent call last):
> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 100, in
> >>> 
> >>> Session.query(with_recursive).set_shard('default').all()
> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
> 2654,
> >>> in all
> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
> 2802,
> >>> in __iter__
> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 28, in
> >>> _execute_and_instances
> >>> shard_id=self._shard_id).execute(
> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line
> 2806,
> >>> in _connection_from_session
> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
> >>> 984, in connection
> >>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 40, in
> >>> get_bind
> >>> original_bind = super(RoutingSession, self).get_bind(mapper,
> clause)
> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
> >>> 1336, in get_bind
> >>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/sql/elements.py", line
> >>> 539, in __bool__
> >>> TypeError: Boolean value of this clause is not defined
> >>>
> 
>  >
>  > Simon
> 
>  >
>  >
>  >
>  > On Fri, Oct 20, 2017 at 3:17 PM, Антонио Антуан 
>  > wrote:
>  >> Really, `mapper` contains this:   >> 0x7fe673fb0a50; group_getter>. But does it changes something? I
>  >> already
>  >> encountered this problem in my code, when I checked sqla-objects
>  >> existance
>  >> without "is not None", project was broken. Is it normal to omit
> that
>  >> condition in sqlalchemy code?
>  >>
>  >> I use:
>  > sqlalchemy.__version__
>  >> '1.0.19'
>  >>
>  >> пятница, 20 октября 2017 г., 16:42:23 UTC+3 пользователь Simon King
>  >> написал:
>  >>>
>  >>> On Fri, Oct 20, 2017 at 2:15 PM, Антонио Антуан <
> a.ch...@gmail.com>
>  >>> wrote:
>  >>> > Hi.
>  >>> > I use my own `RoutingSession` and `RoutingQuery` implementation,
>  >>> > most of
>  >>> > it
>  >>> > inspired by `sqlalchemy.ext.horizontal_shard`:
>  >>> >
>  >>> > class RoutingSession(Session):
>  >>> > def get_bind(self, mapper=None, clause=None, shard_id=None,
>  >>> > **kwargs):
>  >>> > original_bind = None
>  >>> > try:
>  >>> > original_bind = super(RoutingSession,
>  >>> > self).get_bind(mapper,
>  >>> > clause)
>  >>> > except UnboundExecutionError:
>  >>> > # may not be bound
>  >>> > pass
>  >>> > if shard_id is None:
>  >>> > shard_id = TenantIDStorage.get_shard_id()  # just
>  >>> > global
>  >>> > storage
>  >>> > bind_for_shard = self.__binds[shard_id]
>  >>> > if original_bind is not None and original_bind.url ==
>  >>> > bind_for_shard.url:
>  >>> > return original_bind
>  >>> > else:
>  >>> > return bind_for_shard
>  >>> >
>  >>> > def __init__(self, shards=None, query_cls=CachingQuery,
>  >>> > engines_factory=None, **kwargs):
>  >>> > 

Re: [sqlalchemy] mapper existance checks possibly wrong

[Simon King]

What does self._mapper_zero() return in your
RoutingQuery._execute_and_instances method?

Simon

On Wed, Oct 25, 2017 at 11:52 AM, Антонио Антуан  wrote:
> Any news here?
>
> суббота, 21 октября 2017 г., 18:42:47 UTC+3 пользователь Антонио Антуан
> написал:
>>
>> I see that it is not happened when "bind" passed directly to
>> "sessionmaker"
>>
>> сб, 21 окт. 2017 г. в 18:33, Антонио Антуан :
>>>
>>>
>>>
>>> пятница, 20 октября 2017 г., 20:50:52 UTC+3 пользователь Mike Bayer
>>> написал:

 On Fri, Oct 20, 2017 at 11:05 AM, Simon King 
 wrote:
 > The "is not None" is important when checking a variable that may
 > contain a ClauseElement, precisely because ClauseElement defines that
 > __bool__ method.
 >
 > However, in Session.get_bind(), "mapper" is not supposed to contain a
 > ClauseElement. It should either be an instance of
 > sqlalchemy.orm.mapper.Mapper, or None, in which case "if mapper:" is a
 > valid and concise way to write it. Comparing to None might be strictly
 > more accurate, but it shouldn't be necessary.

 agree, "mapper" means "mapper" and it is not supposed to be a
 ClauseElement.   This sounds like arguments are not being passed
 correctly somewhere.   Would need a demonstration script if something
 in SQLAlchemy itself is claimed to be making the mistake.
>>>
>>>
>>> Ok, that code produces mentioned error:
>>> https://gist.github.com/aCLr/113ac292c05bdb01e964d8e9884d6e5f
>>> Traceback (most recent call last):
>>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 100, in
>>> 
>>> Session.query(with_recursive).set_shard('default').all()
>>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line 2654,
>>> in all
>>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line 2802,
>>> in __iter__
>>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 28, in
>>> _execute_and_instances
>>> shard_id=self._shard_id).execute(
>>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line 2806,
>>> in _connection_from_session
>>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
>>> 984, in connection
>>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 40, in
>>> get_bind
>>> original_bind = super(RoutingSession, self).get_bind(mapper, clause)
>>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line
>>> 1336, in get_bind
>>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/sql/elements.py", line
>>> 539, in __bool__
>>> TypeError: Boolean value of this clause is not defined
>>>

 >
 > Simon

 >
 >
 >
 > On Fri, Oct 20, 2017 at 3:17 PM, Антонио Антуан 
 > wrote:
 >> Really, `mapper` contains this: >>> >> 0x7fe673fb0a50; group_getter>. But does it changes something? I
 >> already
 >> encountered this problem in my code, when I checked sqla-objects
 >> existance
 >> without "is not None", project was broken. Is it normal to omit that
 >> condition in sqlalchemy code?
 >>
 >> I use:
 > sqlalchemy.__version__
 >> '1.0.19'
 >>
 >> пятница, 20 октября 2017 г., 16:42:23 UTC+3 пользователь Simon King
 >> написал:
 >>>
 >>> On Fri, Oct 20, 2017 at 2:15 PM, Антонио Антуан 
 >>> wrote:
 >>> > Hi.
 >>> > I use my own `RoutingSession` and `RoutingQuery` implementation,
 >>> > most of
 >>> > it
 >>> > inspired by `sqlalchemy.ext.horizontal_shard`:
 >>> >
 >>> > class RoutingSession(Session):
 >>> > def get_bind(self, mapper=None, clause=None, shard_id=None,
 >>> > **kwargs):
 >>> > original_bind = None
 >>> > try:
 >>> > original_bind = super(RoutingSession,
 >>> > self).get_bind(mapper,
 >>> > clause)
 >>> > except UnboundExecutionError:
 >>> > # may not be bound
 >>> > pass
 >>> > if shard_id is None:
 >>> > shard_id = TenantIDStorage.get_shard_id()  # just
 >>> > global
 >>> > storage
 >>> > bind_for_shard = self.__binds[shard_id]
 >>> > if original_bind is not None and original_bind.url ==
 >>> > bind_for_shard.url:
 >>> > return original_bind
 >>> > else:
 >>> > return bind_for_shard
 >>> >
 >>> > def __init__(self, shards=None, query_cls=CachingQuery,
 >>> > engines_factory=None, **kwargs):
 >>> > super(RoutingSession, self).__init__(query_cls=query_cls,
 >>> > **kwargs)
 >>> > self.__binds = {}
 >>> > self.engines_factory = engines_factory
 >>> > if shards is not None:
 >>> > self.update_shards(**shards)
 >>> >
 >>> > def _add_bind(self, key, bind):
 >>> > self.__binds[key] = bind
 >>> 

Re: [sqlalchemy] mapper existance checks possibly wrong

[Антонио Антуан]

Any news here?

суббота, 21 октября 2017 г., 18:42:47 UTC+3 пользователь Антонио Антуан 
написал:
>
> I see that it is not happened when "bind" passed directly to 
> "sessionmaker" 
>
> сб, 21 окт. 2017 г. в 18:33, Антонио Антуан :
>
>>
>>
>> пятница, 20 октября 2017 г., 20:50:52 UTC+3 пользователь Mike Bayer 
>> написал:
>>
>>> On Fri, Oct 20, 2017 at 11:05 AM, Simon King  
>>> wrote: 
>>> > The "is not None" is important when checking a variable that may 
>>> > contain a ClauseElement, precisely because ClauseElement defines that 
>>> > __bool__ method. 
>>> > 
>>> > However, in Session.get_bind(), "mapper" is not supposed to contain a 
>>> > ClauseElement. It should either be an instance of 
>>> > sqlalchemy.orm.mapper.Mapper, or None, in which case "if mapper:" is a 
>>> > valid and concise way to write it. Comparing to None might be strictly 
>>> > more accurate, but it shouldn't be necessary. 
>>>
>>> agree, "mapper" means "mapper" and it is not supposed to be a 
>>> ClauseElement.   This sounds like arguments are not being passed 
>>> correctly somewhere.   Would need a demonstration script if something 
>>> in SQLAlchemy itself is claimed to be making the mistake. 
>>>
>>
>> Ok, that code produces mentioned error: 
>> https://gist.github.com/aCLr/113ac292c05bdb01e964d8e9884d6e5f
>> Traceback (most recent call last):
>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 100, in 
>> 
>> Session.query(with_recursive).set_shard('default').all()
>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line 2654, 
>> in all
>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line 2802, 
>> in __iter__
>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 28, in 
>> _execute_and_instances
>> shard_id=self._shard_id).execute(
>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/query.py", line 2806, 
>> in _connection_from_session
>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line 
>> 984, in connection
>>   File "/home/anton/Projects/proj/core/run/stuff.py", line 40, in get_bind
>> original_bind = super(RoutingSession, self).get_bind(mapper, clause)
>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/orm/session.py", line 
>> 1336, in get_bind
>>   File "build/bdist.linux-x86_64/egg/sqlalchemy/sql/elements.py", line 
>> 539, in __bool__
>> TypeError: Boolean value of this clause is not defined
>>  
>>
>>> > 
>>> > Simon 
>>>
>> > 
>>> > 
>>> > 
>>> > On Fri, Oct 20, 2017 at 3:17 PM, Антонио Антуан  
>>> wrote: 
>>> >> Really, `mapper` contains this: >> >> 0x7fe673fb0a50; group_getter>. But does it changes something? I 
>>> already 
>>> >> encountered this problem in my code, when I checked sqla-objects 
>>> existance 
>>> >> without "is not None", project was broken. Is it normal to omit that 
>>> >> condition in sqlalchemy code? 
>>> >> 
>>> >> I use: 
>>> > sqlalchemy.__version__ 
>>> >> '1.0.19' 
>>> >> 
>>> >> пятница, 20 октября 2017 г., 16:42:23 UTC+3 пользователь Simon King 
>>> написал: 
>>> >>> 
>>> >>> On Fri, Oct 20, 2017 at 2:15 PM, Антонио Антуан  
>>> wrote: 
>>> >>> > Hi. 
>>> >>> > I use my own `RoutingSession` and `RoutingQuery` implementation, 
>>> most of 
>>> >>> > it 
>>> >>> > inspired by `sqlalchemy.ext.horizontal_shard`: 
>>> >>> > 
>>> >>> > class RoutingSession(Session): 
>>> >>> > def get_bind(self, mapper=None, clause=None, shard_id=None, 
>>> >>> > **kwargs): 
>>> >>> > original_bind = None 
>>> >>> > try: 
>>> >>> > original_bind = super(RoutingSession, 
>>> self).get_bind(mapper, 
>>> >>> > clause) 
>>> >>> > except UnboundExecutionError: 
>>> >>> > # may not be bound 
>>> >>> > pass 
>>> >>> > if shard_id is None: 
>>> >>> > shard_id = TenantIDStorage.get_shard_id()  # just 
>>> global 
>>> >>> > storage 
>>> >>> > bind_for_shard = self.__binds[shard_id] 
>>> >>> > if original_bind is not None and original_bind.url == 
>>> >>> > bind_for_shard.url: 
>>> >>> > return original_bind 
>>> >>> > else: 
>>> >>> > return bind_for_shard 
>>> >>> > 
>>> >>> > def __init__(self, shards=None, query_cls=CachingQuery, 
>>> >>> > engines_factory=None, **kwargs): 
>>> >>> > super(RoutingSession, self).__init__(query_cls=query_cls, 
>>> >>> > **kwargs) 
>>> >>> > self.__binds = {} 
>>> >>> > self.engines_factory = engines_factory 
>>> >>> > if shards is not None: 
>>> >>> > self.update_shards(**shards) 
>>> >>> > 
>>> >>> > def _add_bind(self, key, bind): 
>>> >>> > self.__binds[key] = bind 
>>> >>> > 
>>> >>> > 
>>> >>> > 
>>> >>> > 
>>> >>> > class RoutingQuery(Query): 
>>> >>> > def __init__(self, *args, **kwargs): 
>>> >>> > super(RoutingQuery, self).__init__(*args, **kwargs) 
>>> >>> > self._shard_id =