[sqlalchemy] Re: Correct way of moving relation
Michael, Michael Bayer wrote: oh, duh. do it like this: for purchase in list(aItem.purchase): purchase.cbbottle = bItem I leave it to you as an exercise why this is the case. aItem.purchase is an instrumented list and as such is mutable, is that the right conclusion? Thanks for your help Werner --~--~-~--~~~---~--~~ 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: Getting ForeignKey Before Commit
n00b wrote: why don't you work off the las/previous committed rec id? On Jan 29, 4:05 am, Dejan Mayo dejan.m...@gmail.com wrote: Hi, My code is like that: try: for some_val in some_values: rec = SomeModel() rec.some_val = some_val session.save(rec) session.commit() except: session.rollback() For each record that I'm creating, I need to send an email right after. And each email includes some data about these records, especially the rec.id. Everything looks fine but the problem is getting the rec.id. I've tried: try: for some_val in some_values: rec = SomeModel() rec.some_val = some_val session.save(rec) email(rec=rec) # rec doesn't have id yet so it doesn't work what about doing: session.flush() here? Werner --~--~-~--~~~---~--~~ 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] Using orderedlist with a secondary table
Hi,
I am currently trying to make a relation between Document and Author, where
there is a many to many association which is dealt with by a secondary table
and I am trying to store the position of an author in the author list.
mapper(Paper, document_table, properties={'journal':relation(Journal,
backref='paper'),
'authors':relation(Author,
secondary=papers_to_authors_table,
collection_class=ordering_list('position'),
order_by=[papers_to_authors_table.c.position]),
'keywords':relation(Keyword,
secondary=documents_to_keywords_table)
})
papers_to_authors_table = Table('p2a_association', metadata,
Column('document', Integer,
ForeignKey('documents.document_id')),
Column('author', Integer,
ForeignKey('authors.author_id')),
Column('position', Integer)
)
However when I try to do this:
File Worker.py, line 281, in module
p = Paper(title, date, authors, journal, j_volume, j_issue, keywords,
abstract, None, body, pmid, institution)
File
/cluster/soft/Linux_2.6_64/lib/python2.5/site-packages/SQLAlchemy-0.4.8-py2.5.egg/sqlalchemy/orm/attributes.py,
line 1218, in init
oldinit(instance, *args, **kwargs)
File /cluster/home/nathan/work/workspace/txtmining/Registry.py, line
258, in __init__
self.authors.append(a)
File
/cluster/soft/Linux_2.6_64/lib/python2.5/site-packages/SQLAlchemy-0.4.8-py2.5.egg/sqlalchemy/orm/collections.py,
line 922, in append
fn(self, item)
File
/cluster/soft/Linux_2.6_64/lib/python2.5/site-packages/SQLAlchemy-0.4.8-py2.5.egg/sqlalchemy/ext/orderinglist.py,
line 214, in append
self._order_entity(len(self) - 1, entity, self.reorder_on_append)
File
/cluster/soft/Linux_2.6_64/lib/python2.5/site-packages/SQLAlchemy-0.4.8-py2.5.egg/sqlalchemy/ext/orderinglist.py,
line 202, in _order_entity
have = self._get_order_value(entity)
File
/cluster/soft/Linux_2.6_64/lib/python2.5/site-packages/SQLAlchemy-0.4.8-py2.5.egg/sqlalchemy/ext/orderinglist.py,
line 189, in _get_order_value
return getattr(entity, self.ordering_attr)
AttributeError: 'Author' object has no attribute 'position'
So is there an easy way of performing this functionality using the ordered
list or do I need to do something else?
Many thanks in advance
nathan
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[sqlalchemy] Re: Using orderedlist with a secondary table
-Original Message- From: sqlalchemy@googlegroups.com [mailto:sqlalch...@googlegroups.com] On Behalf Of Nathan Harmston Sent: 30 January 2009 13:15 To: sqlalchemy@googlegroups.com Subject: [sqlalchemy] Using orderedlist with a secondary table Hi, I am currently trying to make a relation between Document and Author, where there is a many to many association which is dealt with by a secondary table and I am trying to store the position of an author in the author list. [snip] So is there an easy way of performing this functionality using the ordered list or do I need to do something else? Many thanks in advance nathan You can't use the 'secondary' mapper argument if you want to be able to use columns in that secondary table. Instead, you need to map a class to your secondary table directly, such that it has 1-many relations with the Document and Author classes. You can then use the 'associationproxy' extension to hide the details. See the docs at http://www.sqlalchemy.org/docs/05/mappers.html#association-pattern and http://www.sqlalchemy.org/docs/05/reference/ext/associationproxy.html#as sociationproxy Hope that helps, Simon --~--~-~--~~~---~--~~ 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: (InterfaceError) connection already closed
On Jan 30, 2009, at 5:50 AM, Alessandro Dentella wrote: Hi, i'm trying to understand how to cope with errors from the database and I don't completely understand the following behaviour. I try to delete a Project that has integrity constrains, so correctly the db complains and SA raises an OperationalError. Right now I'm not trying to understand how to *prevent* this. I just want to understand how to give a message to the user and restore a working situation. [I'm working with postgreSQL and SA 5.0rc4] def delete_obj(obj): print ### deleting obj, repr(obj) try: session.delete(obj) print session.delete:, session.deleted session.commit() except Exception, e: print Problemi..., e.message session.rollback() q = session.query(Project) prj = q.filter_by(id=18).one() print repr(prj) delete_obj(prj) print session.delete:, session.deleted for obj in session: print obj, hex(id(obj)), type(obj) print Project, prj ### this code raises the Interface error where is the problem? the connection (as I tend to believe) or the object 'prj'? What's the state in which is now the object 'prj'? What should I do to go back to the previous situation? What exacltly means InterfaceError - connection already closed. I simply issued a .rollback(), why should it be closed? How should I test if a connection is closed? and how should I open it again? connection already closed is a psycopg2 error indicating that the socket has been shut down. looking at your output, I see a raw execute() occuring within the string conversion of your Project object and theres a module called sqlkit/db/utils.py causing an exception throw. SQLA's rollback then fails too but probably for the same reason. since you're executing directly off of the engine there, it would seem unrelated to the state of the connection related to the session.its not apparent why the socket would be shut down, however, unless the database were restarted perhaps. --~--~-~--~~~---~--~~ 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: find only loaded objects in relation collections
GHZ wrote:
Hi,
I have a Subscriber and an Address table. Subscriber can have many
Addresses
mapper(Subscriber, subscriber_table, properties={
'addresses' : relation(Address, collection_class=Addresses,
backref='customer')})
From the a Subscriber object, I want to inspect all loaded objects in
any collections, but do it quietly - without causing any more to load.
class MyBase(object):
@reconstructor
def __my_init__(self):
self.rules = []
def get_all_rules_on_all_loaded_related_objects(self):
for collection in (p for p in object_mapper
(self).iterate_properties if type(p) is RelationProperty):
# How to access this collection without causing it to
load?
# I want to look at the 'rules' property on all loaded
objects
The collection will be present in the instance's __dict__ if it has been
loaded. So something like
if 'addresses' in self.__dict__:
# loaded, can access self.addresses without triggering db access
-j
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[sqlalchemy] polymorphic_identity not allowed to be zero for base class?
Hi,
[trying to send this again, seems like previous copy got lost in some
moderation queue]
Messing with single-table inheritance in a declarative model, with a
non-abstract base class, I find that querying fails if polymorphic_identity
is 0 (zero). Example:
code begins
from sqlalchemy import Column, Integer, create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
Base = declarative_base()
class Course(Base):
__tablename__ = 'course'
id = Column(Integer, primary_key=True)
course_type = Column(Integer)
__mapper_args__ = {'polymorphic_on':course_type,
'polymorphic_identity':0}
class MultiYearCourse(Course):
__mapper_args__ = {'polymorphic_identity':1}
engine = create_engine('sqlite:///:memory:')
Base.metadata.create_all(bind=engine)
session = sessionmaker(bind=engine)()
myc = MultiYearCourse()
myc.name = uComputer Graphics
c = Course()
c.name = uSociology
session.add(c)
session.add(myc)
session.commit()
print MYC: %s % myc
print C: %s % c
query = session.query(Course)
print Query: %s % query
print Results: %s % query.all()
code ends
That last line fails with an AssertionError:
output begins
MYC: __main__.MultiYearCourse object at 0xcf7d30
C: __main__.Course object at 0xcf7d70
Query: SELECT course.id AS course_id, course.course_type AS
course_course_type
FROM course
Traceback (most recent call last):
File /Users/gthb/Documents/workspace/test/src/sqlalchemytest.py, line
31, in module
print Results: %s % query.all()
File
/Users/gthb/Library/Python/2.5/site-packages/SQLAlchemy-0.5.2-py2.5.egg/sqlalchemy/orm/query.py,
line 1186, in all
return list(self)
File
/Users/gthb/Library/Python/2.5/site-packages/SQLAlchemy-0.5.2-py2.5.egg/sqlalchemy/orm/query.py,
line 1341, in instances
rows = [process[0](context, row) for row in fetch]
File
/Users/gthb/Library/Python/2.5/site-packages/SQLAlchemy-0.5.2-py2.5.egg/sqlalchemy/orm/query.py,
line 1942, in main
return _instance(row, None)
File
/Users/gthb/Library/Python/2.5/site-packages/SQLAlchemy-0.5.2-py2.5.egg/sqlalchemy/orm/mapper.py,
line 1557, in _instance
_instance = polymorphic_instances[discriminator]
File
/Users/gthb/Library/Python/2.5/site-packages/SQLAlchemy-0.5.2-py2.5.egg/sqlalchemy/util.py,
line 71, in __missing__
self[key] = val = self.creator(key)
File
/Users/gthb/Library/Python/2.5/site-packages/SQLAlchemy-0.5.2-py2.5.egg/sqlalchemy/orm/mapper.py,
line 1695, in configure_subclass_mapper
raise AssertionError(No such polymorphic_identity %r is defined %
discriminator)
AssertionError: No such polymorphic_identity 0 is defined
output ends
But if I exchange the polymorphic identities, so the base class gets the 1
and the subclass gets the 0, then it runs just fine!
It seems to me that this can't be intentional — don't see a reason for it,
and the docs do not mention any particular restrictions on values of
polymorphic_identity.
Regards,
- Gulli
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[sqlalchemy] Re: polymorphic_identity not allowed to be zero for base class?
its likely a bug. there are some boolean tests for
polymorphic_identity in mapper.py which should be changed to is
None.
On Jan 30, 2009, at 11:58 AM, Gunnlaugur Thor Briem wrote:
Hi,
[trying to send this again, seems like previous copy got lost in
some moderation queue]
Messing with single-table inheritance in a declarative model, with a
non-abstract base class, I find that querying fails if
polymorphic_identity is 0 (zero). Example:
code begins
from sqlalchemy import Column, Integer, create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
Base = declarative_base()
class Course(Base):
__tablename__ = 'course'
id = Column(Integer, primary_key=True)
course_type = Column(Integer)
__mapper_args__ = {'polymorphic_on':course_type,
'polymorphic_identity':0}
class MultiYearCourse(Course):
__mapper_args__ = {'polymorphic_identity':1}
engine = create_engine('sqlite:///:
memory:')
Base.metadata.create_all(bind=engine)
session = sessionmaker(bind=engine)()
myc = MultiYearCourse()
myc.name = uComputer Graphics
c = Course()
c.name = uSociology
session.add(c)
session.add(myc)
session.commit()
print MYC: %s % myc
print C: %s % c
query = session.query(Course)
print Query: %s % query
print Results: %s % query.all()
code ends
That last line fails with an AssertionError:
output begins
MYC: __main__.MultiYearCourse object at 0xcf7d30
C: __main__.Course object at 0xcf7d70
Query: SELECT course.id AS course_id, course.course_type AS
course_course_type
FROM course
Traceback (most recent call last):
File /Users/gthb/Documents/workspace/test/src/sqlalchemytest.py,
line 31, in module
print Results: %s % query.all()
File /Users/gthb/Library/Python/2.5/site-packages/
SQLAlchemy-0.5.2-py2.5.egg/sqlalchemy/orm/query.py, line 1186, in all
return list(self)
File /Users/gthb/Library/Python/2.5/site-packages/
SQLAlchemy-0.5.2-py2.5.egg/sqlalchemy/orm/query.py, line 1341, in
instances
rows = [process[0](context, row) for row in fetch]
File /Users/gthb/Library/Python/2.5/site-packages/
SQLAlchemy-0.5.2-py2.5.egg/sqlalchemy/orm/query.py, line 1942, in
main
return _instance(row, None)
File /Users/gthb/Library/Python/2.5/site-packages/
SQLAlchemy-0.5.2-py2.5.egg/sqlalchemy/orm/mapper.py, line 1557, in
_instance
_instance = polymorphic_instances[discriminator]
File /Users/gthb/Library/Python/2.5/site-packages/
SQLAlchemy-0.5.2-py2.5.egg/sqlalchemy/util.py, line 71, in
__missing__
self[key] = val = self.creator(key)
File /Users/gthb/Library/Python/2.5/site-packages/
SQLAlchemy-0.5.2-py2.5.egg/sqlalchemy/orm/mapper.py, line 1695, in
configure_subclass_mapper
raise AssertionError(No such polymorphic_identity %r is
defined % discriminator)
AssertionError: No such polymorphic_identity 0 is defined
output ends
But if I exchange the polymorphic identities, so the base class gets
the 1 and the subclass gets the 0, then it runs just fine!
It seems to me that this can't be intentional — don't see a reason
for it, and the docs do not mention any particular restrictions on
values of polymorphic_identity.
Regards,
- Gulli
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[sqlalchemy] Re: polymorphic_identity not allowed to be zero for base class?
Would None (ie. SQL NULL) be a valid polymorphic identity?
-Original Message-
From: sqlalchemy@googlegroups.com
[mailto:sqlalch...@googlegroups.com] On Behalf Of Michael Bayer
Sent: 30 January 2009 17:06
To: sqlalchemy@googlegroups.com
Subject: [sqlalchemy] Re: polymorphic_identity not allowed to
be zero for base class?
its likely a bug. there are some boolean tests for
polymorphic_identity in mapper.py which should be changed
to is None.
On Jan 30, 2009, at 11:58 AM, Gunnlaugur Thor Briem wrote:
Hi,
[trying to send this again, seems like previous copy
got lost in some moderation queue]
Messing with single-table inheritance in a declarative
model, with a non-abstract base class, I find that querying
fails if polymorphic_identity is 0 (zero). Example:
code begins
from sqlalchemy import Column, Integer, create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
Base = declarative_base()
class Course(Base):
__tablename__ = 'course'
id = Column(Integer, primary_key=True)
course_type = Column(Integer)
__mapper_args__ = {'polymorphic_on':course_type,
'polymorphic_identity':0}
class MultiYearCourse(Course):
__mapper_args__ = {'polymorphic_identity':1}
engine = create_engine('sqlite:///:
memory:')
Base.metadata.create_all(bind=engine)
session = sessionmaker(bind=engine)()
myc = MultiYearCourse()
myc.name http://myc.name/ = uComputer Graphics
c = Course()
c.name http://c.name/ = uSociology
session.add(c)
session.add(myc)
session.commit()
print MYC: %s % myc
print C: %s % c
query = session.query(Course)
print Query: %s % query
print Results: %s % query.all()
code ends
That last line fails with an AssertionError:
output begins
MYC: __main__.MultiYearCourse object at 0xcf7d30
C: __main__.Course object at 0xcf7d70
Query: SELECT course.id http://course.id/ AS
course_id, course.course_type AS course_course_type
FROM course
Traceback (most recent call last):
File
/Users/gthb/Documents/workspace/test/src/sqlalchemytest.py,
line 31, in module
print Results: %s % query.all()
File
/Users/gthb/Library/Python/2.5/site-packages/SQLAlchemy-0.5.2
-py2.5.egg/sqlalchemy/orm/query.py, line 1186, in all
return list(self)
File
/Users/gthb/Library/Python/2.5/site-packages/SQLAlchemy-0.5.2
-py2.5.egg/sqlalchemy/orm/query.py, line 1341, in instances
rows = [process[0](context, row) for row in fetch]
File
/Users/gthb/Library/Python/2.5/site-packages/SQLAlchemy-0.5.2
-py2.5.egg/sqlalchemy/orm/query.py, line 1942, in main
return _instance(row, None)
File
/Users/gthb/Library/Python/2.5/site-packages/SQLAlchemy-0.5.2
-py2.5.egg/sqlalchemy/orm/mapper.py, line 1557, in _instance
_instance = polymorphic_instances[discriminator]
File
/Users/gthb/Library/Python/2.5/site-packages/SQLAlchemy-0.5.2
-py2.5.egg/sqlalchemy/util.py, line 71, in __missing__
self[key] = val = self.creator(key)
File
/Users/gthb/Library/Python/2.5/site-packages/SQLAlchemy-0.5.2
-py2.5.egg/sqlalchemy/orm/mapper.py, line 1695, in
configure_subclass_mapper
raise AssertionError(No such polymorphic_identity
%r is defined % discriminator)
AssertionError: No such polymorphic_identity 0 is defined
output ends
But if I exchange the polymorphic identities, so the
base class gets the 1 and the subclass gets the 0, then it
runs just fine!
It seems to me that this can't be intentional - don't
see a reason for it, and the docs do not mention any
particular restrictions on values of polymorphic_identity.
Regards,
- Gulli
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[sqlalchemy] Re: polymorphic_identity not allowed to be zero for base class?
On Jan 30, 2009, at 12:19 PM, King Simon-NFHD78 wrote: Would None (ie. SQL NULL) be a valid polymorphic identity? it becomes that issue where we just need some kind of constant to represent THIS_IS_NOT_DEFINED, so that we know when polymorphic_identity is defined or not. it's a straightforward patch. Although we'd also need to adapt some expressions such as identity IN (x, y, z) to account for NULL, so, supporting NULL is a little more work. --~--~-~--~~~---~--~~ 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: polymorphic_identity not allowed to be zero for base class?
-Original Message- From: sqlalchemy@googlegroups.com [mailto:sqlalch...@googlegroups.com] On Behalf Of Michael Bayer Sent: 30 January 2009 17:25 To: sqlalchemy@googlegroups.com Subject: [sqlalchemy] Re: polymorphic_identity not allowed to be zero for base class? On Jan 30, 2009, at 12:19 PM, King Simon-NFHD78 wrote: Would None (ie. SQL NULL) be a valid polymorphic identity? it becomes that issue where we just need some kind of constant to represent THIS_IS_NOT_DEFINED, so that we know when polymorphic_identity is defined or not. it's a straightforward patch. Although we'd also need to adapt some expressions such as identity IN (x, y, z) to account for NULL, so, supporting NULL is a little more work. Thanks - I was only asking out of curiosity. I have no need for it personally. Cheers, Simon --~--~-~--~~~---~--~~ 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: (InterfaceError) connection already closed
connection already closed is a psycopg2 error indicating that the
socket has been shut down. looking at your output, I see a raw
execute() occuring within the string conversion of your Project object
and theres a module called sqlkit/db/utils.py causing an exception
throw. SQLA's rollback then fails too but probably for the same
reason. since you're executing directly off of the engine there, it
would seem unrelated to the state of the connection related to the
session.its not apparent why the socket would be shut down,
however, unless the database were restarted perhaps.
sorry for not seeing that error myself, on the other hand: no postgres has
never been shut down. Anyhow I got rid of that code (an on the fly __str__
builder), I go little further but get errors again.
1. prj is fetched from db by a session.query() id=18
2. I try to delete it, failing due to constraints on the db
3. session.rollback()
4. print prj.name - error
4b. session.expunge_all()
session.flush()
fetch a new one (id=20) -- error (reported below on id=18)
So back to the question: in which state is 'prj' after failing deletion and
after rolling back?
Even if I 'session.expunge(prj)' I cannot refetch a new project (even a
different one...)
I'm really puzzled...
sandro
*:-)
def delete_obj(obj):
print ### deleting obj, repr(obj)
try:
session.delete(obj)
print session.delete:, session.deleted
session.commit()
except Exception, e:
print Problems..., e.message
session.rollback()
#session.bind.connect()
q = session.query(Project)
prj = q.filter_by(id=18).one()
print repr(prj)
delete_obj(prj)
print session.deleted:, session.deleted
for obj in session:
print obj, hex(id(obj)), type(obj)
session.expunge_all()
session.flush()
prj = q.filter_by(id=20).one() ## a different project
##
san...@bluff:/misc/src/hg/py/fossati/fossati$ python test.py
models.ticket.Project object at 0x88a4d8c
### deleting obj models.ticket.Project object at 0x88a4d8c
session.delete: IdentitySet([models.ticket.Project object at 0x88a4d8c])
Problems... (OperationalError) ERROR: update or delete on table
ticket_project violates foreign key constraint
timereport_report_job_id_fkey on table timereport_report
DETAIL: Key (id)=(18) is still referenced from table timereport_report.
session.deleted: IdentitySet([])
obj 0x88a4d8c class 'models.ticket.Project'
obj 0x88b6c4c class 'models.ticket.Organization'
obj 0x88b61cc class 'models.cliente.User'
No handlers could be found for logger sqlalchemy.pool.QueuePool.0x...cb8c
Traceback (most recent call last):
File test.py, line 36, in module
prj = q.filter_by(id=20).one()
File /home/misc/src/sqlalchemy/sqlalchemy-svn/lib/sqlalchemy/orm/query.py,
line 1061, in one
ret = list(self[0:2])
File /home/misc/src/sqlalchemy/sqlalchemy-svn/lib/sqlalchemy/orm/query.py,
line 961, in __getitem__
return list(res)
File /home/misc/src/sqlalchemy/sqlalchemy-svn/lib/sqlalchemy/orm/query.py,
line 1101, in __iter__
return self._execute_and_instances(context)
File /home/misc/src/sqlalchemy/sqlalchemy-svn/lib/sqlalchemy/orm/query.py,
line 1104, in _execute_and_instances
result = self.session.execute(querycontext.statement, params=self._params,
mapper=self._mapper_zero_or_none())
File
/home/misc/src/sqlalchemy/sqlalchemy-svn/lib/sqlalchemy/orm/session.py, line
755, in execute
clause, params or {})
File
/home/misc/src/sqlalchemy/sqlalchemy-svn/lib/sqlalchemy/engine/base.py, line
824, in execute
return Connection.executors[c](self, object, multiparams, params)
File
/home/misc/src/sqlalchemy/sqlalchemy-svn/lib/sqlalchemy/engine/base.py, line
874, in _execute_clauseelement
return self.__execute_context(context)
File
/home/misc/src/sqlalchemy/sqlalchemy-svn/lib/sqlalchemy/engine/base.py, line
896, in __execute_context
self._cursor_execute(context.cursor, context.statement,
context.parameters[0], context=context)
File
/home/misc/src/sqlalchemy/sqlalchemy-svn/lib/sqlalchemy/engine/base.py, line
950, in _cursor_execute
self._handle_dbapi_exception(e, statement, parameters, cursor, context)
File
/home/misc/src/sqlalchemy/sqlalchemy-svn/lib/sqlalchemy/engine/base.py, line
931, in _handle_dbapi_exception
raise exc.DBAPIError.instance(statement, parameters, e,
connection_invalidated=is_disconnect)
sqlalchemy.exc.OperationalError: (OperationalError) update or delete on table
ticket_project violates foreign key constraint
timereport_report_job_id_fkey on table timereport_report
DETAIL: Key (id)=(18) is still referenced from table timereport_report.
'SELECT anon_1.ticket_project_id AS anon_1_ticket_project_id,
anon_1.ticket_project_date_create AS anon_1_ticket_project_date_create,
anon_1.ticket_project_date_last_modify AS
anon_1_ticket_project_date_last_modify,
[sqlalchemy] Filtering lazy='dynamic' collection on class type (single-table inheritance)
Hi, I did a quick search but couldn't find the right way to do this in SA. For the sake of example, I have a many-to-many relationshp between Book and Reader. The 'books' property of reader is loaded using lazy='dynamic'. And, finally, Book is mapped with single-table inheritance and has subclasses for various genres. -- this is just an example :) This works: reader = session.query(Reader).first() mysterybooks = reader.books.filter (Book.genre==MysteryBook.DESCRIMINATOR_KEY) However, this doesn't feel like the *right* way. I experimented with various forms of of_type() but didn't get it to work. I'm sure I'm just not fully understanding how that is supposed to work. Thanks in advance! Hans --~--~-~--~~~---~--~~ 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: (InterfaceError) connection already closed
On Jan 30, 2009, at 12:38 PM, Alessandro Dentella wrote: connection already closed is a psycopg2 error indicating that the socket has been shut down. looking at your output, I see a raw execute() occuring within the string conversion of your Project object and theres a module called sqlkit/db/utils.py causing an exception throw. SQLA's rollback then fails too but probably for the same reason. since you're executing directly off of the engine there, it would seem unrelated to the state of the connection related to the session.its not apparent why the socket would be shut down, however, unless the database were restarted perhaps. sorry for not seeing that error myself, on the other hand: no postgres has never been shut down. Anyhow I got rid of that code (an on the fly __str__ builder), I go little further but get errors again. 1. prj is fetched from db by a session.query() id=18 2. I try to delete it, failing due to constraints on the db 3. session.rollback() 4. print prj.name - error 4b. session.expunge_all() session.flush() fetch a new one (id=20) -- error (reported below on id=18) So back to the question: in which state is 'prj' after failing deletion and after rolling back? its in the same state as that which it first got loaded, i.e. not marked as deleted. all of its attributes are also expired.the stack trace you posted doesn't make sense to me though, as its issuing a SELECT statement but PG is raising an exception for an UPDATE / DELETE ? I've never seen that before. If you can provide a self- contained test case which reproduces that behavior we can try it out. --~--~-~--~~~---~--~~ 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: Filtering lazy='dynamic' collection on class type (single-table inheritance)
On Jan 30, 2009, at 1:39 PM, Hans Lellelid wrote: Hi, I did a quick search but couldn't find the right way to do this in SA. For the sake of example, I have a many-to-many relationshp between Book and Reader. The 'books' property of reader is loaded using lazy='dynamic'. And, finally, Book is mapped with single-table inheritance and has subclasses for various genres. -- this is just an example :) This works: reader = session.query(Reader).first() mysterybooks = reader.books.filter (Book.genre==MysteryBook.DESCRIMINATOR_KEY) However, this doesn't feel like the *right* way. I experimented with various forms of of_type() but didn't get it to work. I'm sure I'm just not fully understanding how that is supposed to work. of_type() is currently only implemented for a RelationProperty and takes effect for EXISTS subqueries generated by has()/any() and query.join().So for the dynamic loader's list of books, what you're doing is the best option we have at the moment. it seems like of_type() existing on Query as a generative method would be the way to go here...until someone says query(A, B, C).of_type(A). --~--~-~--~~~---~--~~ 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: Filtering lazy='dynamic' collection on class type (single-table inheritance)
On Jan 30, 2:37 pm, Michael Bayer mike...@zzzcomputing.com wrote: On Jan 30, 2009, at 1:39 PM, Hans Lellelid wrote: Hi, I did a quick search but couldn't find the right way to do this in SA. For the sake of example, I have a many-to-many relationshp between Book and Reader. The 'books' property of reader is loaded using lazy='dynamic'. And, finally, Book is mapped with single-table inheritance and has subclasses for various genres. -- this is just an example :) This works: reader = session.query(Reader).first() mysterybooks = reader.books.filter (Book.genre==MysteryBook.DESCRIMINATOR_KEY) However, this doesn't feel like the *right* way. I experimented with various forms of of_type() but didn't get it to work. I'm sure I'm just not fully understanding how that is supposed to work. of_type() is currently only implemented for a RelationProperty and takes effect for EXISTS subqueries generated by has()/any() and query.join(). So for the dynamic loader's list of books, what you're doing is the best option we have at the moment. it seems like of_type() existing on Query as a generative method would be the way to go here...until someone says query(A, B, C).of_type(A). :) -- Ok, if what I'm doing is right, I'll leave it there. It does work fine afterall, but obviously is a little less resilient to me changing my inheritance mapping strategy down the road. (Not that I plan to...) Thanks! Hans --~--~-~--~~~---~--~~ 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: Equivalent of UPDATE ... WHERE ... in ORM?
Perfect - thanks Mike!
As I'm using 0.4 (sorry, neglected to mention that) I've gone for the
table.update(...).execute() option and it works a treat.
On Jan 25, 12:25 am, Michael Bayer mike...@zzzcomputing.com wrote:
the update() method on Query accomplishes this. Make sure you read
the docstring for it which describes some various behaviors you'll
want to be aware of.
alternatively, any SQL expression, like table.update(), UPDATE
table can be issued within the ORM's transaction using
session.execute().
On Jan 24, 2009, at 7:14 PM, James wrote:
Hi,
Is there a way to update a large number of objects without looping
through each one, using SA's ORM?
E.g.
I want to achieve the following:
for o in session.query(MyClass).filter_by(prop='some value'):
o.prop = 'new value'
session.update(o)
Without fetching and saving each object from the database. I.e.
something which would produce SQL like this:
UPDATE `my_class` SET `prop`='new value' WHERE `prop` = 'some value'
If not, am I safe mixing and matching ORM operations with SQL
operations like:
u = my_classes.update(my_class.c.prop=='some value'), values=
{'prop':'new value'})?
Thanks!
James
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