Here's a stripped down version in a single file. It shows only a single
occasion of 'result' object appearing. The longer version above shows all.
On Sunday, July 19, 2015 at 9:09:01 PM UTC+2, Dirk Makowski wrote:
>
> Thanks for looking into it. Sorry about 7z, it's an archive. Please see
> the revised attachment.
>
> In principle, I'm converting the result from a query into a list of dicts.
>
> data = []
> rs = sess.query(...)
> for r in rs:
> data.append(dictate(r))
>
> In function dictate() is the call to inspect(). Until SA 0.9.9 it worked
> fine. With version 1.0.6 sometimes the call to inspect() fails with
> honestly that error message. It depends on what was queried:
> - a single ORM object: OK
> - hand-made SQL (sa.text()): OK
> - several joined ORM objects: FAIL
> - mixture of ORM objects and columns: FAIL
>
> Attached script goes through these situations and shows exactly what
> happens.
>
>
> On Sunday, July 19, 2015 at 6:28:07 PM UTC+2, Michael Bayer wrote:
>>
>>
>>
>> On 7/19/15 11:58 AM, Dirk Makowski wrote:
>>
>> Hello all,
>>
>> some time ago I wrote a function to mogrify SA query results into a
>> list of dicts. It uses the inspector to determine columns etc. Up until SA
>> 0.9.9 it worked well. However, after an upgrade of SA to 1.0.6 in some
>> circumstances I get this error:
>>
>> No inspection system is available for object of type <class
>> 'sqlalchemy.util._collections.result'>
>>
>> What previously had been a Python type or ORM type now is an ominous
>> 'result'.
>>
>> Hopefully you can give some pointers about what it is and how I could
>> fix my function. A test case with more info in the sources is attached.
>> Apart from SA it does have no external dependencies.
>>
>>
>> The error is that you are calling inspect() on something that does not
>> support inspection. There's no object in util._collections called "result"
>> so I don't know what that is.
>>
>>
>
>> Also I don't know what a "7z" file is. Can you please send a single,
>> very succinct .py file with a simple illustration of your error? Thanks.
>>
>>
>>
>> Thank you,
>>
>> Dirk
>>
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#!/usr/bin/env python
# ==================================================================
# This is just setup. The real action is at the bottom
# ==================================================================
# from pprint import pprint
import sqlalchemy as sa
from sqlalchemy.exc import NoInspectionAvailable
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
import sqlalchemy.util._collections
DbEngine = sa.create_engine('sqlite:///:memory:', echo=False)
DbBase = declarative_base()
DbSession = sessionmaker(bind=DbEngine)
class Smeagol(DbBase):
__tablename__ = 'smeagol'
id = sa.Column(sa.Integer(), nullable=False, primary_key=True)
who = sa.Column(sa.Unicode(255), nullable=False)
def __repr__(self):
return "<{cls}(id={id}, who='{who}')>".format(
cls=self.__class__.__name__, id=self.id, who=self.who)
class Deagol(DbBase):
__tablename__ = 'deagol'
id = sa.Column(sa.Integer(), nullable=False, primary_key=True)
who_id = sa.Column(sa.Integer(), nullable=False)
what = sa.Column(sa.Unicode(255), nullable=False)
whom_id = sa.Column(sa.Integer(), nullable=True)
def __repr__(self):
return "<{cls}(id={id}, who_id={who}, what='{what}', whom_id={whom})>".format(
cls=self.__class__.__name__, id=self.id, who=self.who_id,
what=self.what, whom=self.whom_id)
def is_1xx():
return sa.__version__.startswith('1')
def bootstrap(sess):
DbBase.metadata.create_all(DbEngine)
# Yeah, I could have used orm relationships to init, but I didn't
me = Smeagol(who='Me')
sess.add(me)
myself = Smeagol(who='Myself')
sess.add(myself)
i = Smeagol(who='I')
sess.add(i)
sess.flush()
sess.add(Deagol(who_id=i.id, what='hate', whom_id=myself.id))
sess.add(Deagol(who_id=i.id, what="don't like", whom_id=me.id))
sess.add(Deagol(who_id=myself.id, what="is bff of", whom_id=me.id))
# Yes, I want a missing right side
sess.add(Deagol(who_id=me.id, what="wtf? no SO?", whom_id=None))
sess.flush()
def perform_query(sess):
who = sa.orm.aliased(Smeagol, name='Who')
what = sa.orm.aliased(Deagol, name='What')
whom = sa.orm.aliased(Smeagol, name='Whom')
rs = sess.query(
who, what, whom
).outerjoin(
what, what.who_id == who.id
).outerjoin(
whom, what.whom_id == whom.id
).order_by(
who.who.asc()
)
return rs
# ==================================================================
# Real action begins here
# ==================================================================
def process_keyed_tuple(kt):
for i in kt:
if i is not None:
sa.inspect(i) # discard result, just show that inspect() works
def process_object(o):
sa.inspect(o) # discard result, just show that inspect() works
def dictate(r):
if is_1xx():
# Need to use name, since there is no class 'result'
assert type(r).__name__ == 'result'
else:
assert type(r) == sqlalchemy.util._collections.KeyedTuple
# KeyedTuples are recognized by the real function dictate(), iterated over
# and each item gets inspected
if isinstance(r, sqlalchemy.util._collections.KeyedTuple):
process_keyed_tuple(r)
else:
# This type is unknown, then treated as an object and inspected(),
# which fails.
process_object(r)
def main():
sess = DbSession()
bootstrap(sess)
rs = perform_query(sess)
for r in rs:
dictate(r) # results not needed here
print('Finished.')
if __name__ == '__main__':
main()
