On Thu, Jan 4, 2018 at 3:33 PM, sector119 <sector...@gmail.com> wrote:
> Thank you, Mike, but I need something like this
>
>
> type_coerce(
>
> Database.meters_readings[
>
> func.generate_subscripts(Database.meters_readings, 1)
>
> ], type_=ARRAY(Text)
>
> )[1]
>
>
> Database.meters_readings is two-dimensional array like [ ['1', '2', '3'],
> ['4', '5', '6'] ], so
okey doke, give your array two dimensions:
>>> f = func.generate_subscripts(column('x'), type_=ARRAY(Integer,
>>> dimensions=2))
>>> print f[1][2]
(generate_subscripts(x))[:generate_subscripts_1][:param_1]
>
> Database.meters_readings[func.generate_subscripts.....] must return ['1',
> '2', '3'] or ['4', '5', '6'],
>
> and than I want to get 1-st or second element of this "sub-array"
>
>
> func.generate_subscripts have to return int and it is Ok, but why I can't
> get that "sub-array" without type_coerce?
>
>
>
> четверг, 4 января 2018 г., 17:48:56 UTC+2 пользователь Mike Bayer написал:
>>
>> On Thu, Jan 4, 2018 at 6:49 AM, sector119 <sect...@gmail.com> wrote:
>> > Hello,
>> >
>> >
>> > I try to rewrite "meters_readings[generate_subscripts(meters_readings,
>> > 1)][1]" from plain sql query that works
>> >
>> > with sqlalchemy and
>> >
>> > Database.meters_readings[func.generate_subscripts(Database.meters_readings,
>> > 1)][1] doesn't work
>>
>>
>> your func.generate_subscripts() function doesn't know that it needs to
>> return a datatype that fulfills the "Indexable" contract, that of
>> ARRAY, JSON and HSTORE (though PG documents this as returning "setof",
>> that supports indexing? shrugs). You need to give it the type you
>> need, which I guess in this case the closest is ARRAY:
>>
>> >>> f = func.generate_subscripts(column('q'), 1, type_=ARRAY(Integer))
>> >>> print f[5]
>> (generate_subscripts(q, :generate_subscripts_1))[:generate_subscripts_2]
>>
>>
>>
>>
>> >
>> > I get NotImplementedError: Operator 'getitem' is not supported on this
>> > expression
>> >
>> >
>> > Is it possible?
>> >
>> >
>> >
>> > def get_person_meters_q(dbsession, person_id):
>> > database = dbsession.query(
>> > Database.person_id,
>> > Database.service_id,
>> > Database.person_id_internal,
>> > Database.meters_readings,
>> >
>> >
>> > (Database.meters_readings[func.generate_subscripts(Database.meters_readings,
>> > 1)][1]).label('meter_id'),
>> >
>> >
>> > (Database.meters_readings[func.generate_subscripts(Database.meters_readings,
>> > 1)][2]).label('organization_reading'),
>> > Database.date
>> > ).subquery()
>> >
>> > meter_readings = dbsession.query(
>> > MeterReading.user_id,
>> > MeterReading.reading
>> > ). \
>> > distinct(
>> > MeterReading.service_id,
>> > MeterReading.person_id_internal,
>> > MeterReading.meter_id). \
>> > filter(
>> > and_(
>> > MeterReading.person_id == database.c.person_id,
>> > MeterReading.service_id == database.c.service_id,
>> > MeterReading.meter_id == database.c.meter_id,
>> > MeterReading.commit_date > database.c.date,
>> > MeterReading.rollback_date == None,
>> > MeterReading.reading != None
>> > )
>> > ). \
>> > order_by(
>> > MeterReading.service_id,
>> > MeterReading.person_id_internal,
>> > MeterReading.meter_id,
>> > MeterReading.commit_date.desc(),
>> > MeterReading.commit_time.desc()
>> > ).subquery().lateral()
>> >
>> > q = dbsession.query(
>> > meter_readings,
>> > database
>> > ). \
>> > select_from(database). \
>> > outerjoin(meter_readings, true()). \
>> > filter(Database.person_id == person_id)
>> >
>> > return q
>> >
>> >
>> >
>> > File
>> > "/home/sector119/PycharmProjects/epsilon/epsilon/scripts/testdb.py",
>> > line 98, in get_person_meters_q
>> >
>> >
>> > (Database.meters_readings[func.generate_subscripts(Database.meters_readings,
>> > 1)][1]).label('meter_id'),
>> > File
>> >
>> > "/home/sector119/PythonVirtualEnv/epsilon/lib/python3.5/site-packages/sqlalchemy/sql/operators.py",
>> > line 411, in __getitem__
>> > return self.operate(getitem, index)
>> > File
>> >
>> > "/home/sector119/PythonVirtualEnv/epsilon/lib/python3.5/site-packages/sqlalchemy/sql/elements.py",
>> > line 692, in operate
>> > return op(self.comparator, *other, **kwargs)
>> > File
>> >
>> > "/home/sector119/PythonVirtualEnv/epsilon/lib/python3.5/site-packages/sqlalchemy/sql/operators.py",
>> > line 411, in __getitem__
>> > return self.operate(getitem, index)
>> > File "<string>", line 1, in <lambda>
>> > File
>> >
>> > "/home/sector119/PythonVirtualEnv/epsilon/lib/python3.5/site-packages/sqlalchemy/sql/type_api.py",
>> > line 63, in operate
>> > return o[0](self.expr, op, *(other + o[1:]), **kwargs)
>> > File
>> >
>> > "/home/sector119/PythonVirtualEnv/epsilon/lib/python3.5/site-packages/sqlalchemy/sql/default_comparator.py",
>> > line 192, in _getitem_impl
>> > _unsupported_impl(expr, op, other, **kw)
>> > File
>> >
>> > "/home/sector119/PythonVirtualEnv/epsilon/lib/python3.5/site-packages/sqlalchemy/sql/default_comparator.py",
>> > line 197, in _unsupported_impl
>> > "this expression" % op.__name__)
>> > NotImplementedError: Operator 'getitem' is not supported on this
>> > expression
>> >
>> > --
>> > 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.
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>
> --
> 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.
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--
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.
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