[sqlalchemy] Elixir question
Hi, I am trying to sote pairs in a table as follows:
#--
from elixir import *
metadata.bind = sqlite:///:memory:
metadata.bind.echo = False
class Pairs(Entity):
name = Field(String(50), primary_key = True)
other = OneToOne('Pairs', inverse = 'other')
def __init__(self, name):
self.name = name
def pair(name1, name2):
p1, p2 = Pairs(name1), Pairs(name2)
p1.other = p2
if __name__ == '__main__':
setup_all()
create_all()
pair('p1', 'p2')
#--
I am not very famiiar with SQL etc. but logically this seems possible
(please orrect me if I am wrong). However I get the following error:
File D:\Documents\Code\Eclipse\workspace\SQLAdata\src\tests.py, line
22, in module
setup_all()
File build\bdist.win-amd64\egg\elixir\__init__.py, line 94, in
setup_all
File build\bdist.win-amd64\egg\elixir\entity.py, line 951, in
setup_entities
File build\bdist.win-amd64\egg\elixir\entity.py, line 198, in
create_pk_cols
File build\bdist.win-amd64\egg\elixir\entity.py, line 481, in
call_builders
File build\bdist.win-amd64\egg\elixir\relationships.py, line 448,
in create_pk_cols
File build\bdist.win-amd64\egg\elixir\relationships.py, line 791,
in create_keys
File build\bdist.win-amd64\egg\elixir\relationships.py, line 521,
in inverse
AssertionError: Relationships 'other' in entity 'Pair' and 'other' in
entity 'Pair' cannot be inverse of each other because their types do
not form a valid combination.
Can anyone help me to understand the error and possibly fix it?
Thanks in advance, Lars
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[sqlalchemy] Re: Elixir question
I should probably make the pair method:
def pair(name1, name2):
p1, p2 = Pairs(name1), Pairs(name2)
p1.other = p2
p2.other = p1
On Feb 3, 11:57 am, lars van gemerden l...@rational-it.com wrote:
Hi, I am trying to sote pairs in a table as follows:
#--
from elixir import *
metadata.bind = sqlite:///:memory:
metadata.bind.echo = False
class Pairs(Entity):
name = Field(String(50), primary_key = True)
other = OneToOne('Pairs', inverse = 'other')
def __init__(self, name):
self.name = name
def pair(name1, name2):
p1, p2 = Pairs(name1), Pairs(name2)
p1.other = p2
if __name__ == '__main__':
setup_all()
create_all()
pair('p1', 'p2')
#--
I am not very famiiar with SQL etc. but logically this seems possible
(please orrect me if I am wrong). However I get the following error:
File D:\Documents\Code\Eclipse\workspace\SQLAdata\src\tests.py, line
22, in module
setup_all()
File build\bdist.win-amd64\egg\elixir\__init__.py, line 94, in
setup_all
File build\bdist.win-amd64\egg\elixir\entity.py, line 951, in
setup_entities
File build\bdist.win-amd64\egg\elixir\entity.py, line 198, in
create_pk_cols
File build\bdist.win-amd64\egg\elixir\entity.py, line 481, in
call_builders
File build\bdist.win-amd64\egg\elixir\relationships.py, line 448,
in create_pk_cols
File build\bdist.win-amd64\egg\elixir\relationships.py, line 791,
in create_keys
File build\bdist.win-amd64\egg\elixir\relationships.py, line 521,
in inverse
AssertionError: Relationships 'other' in entity 'Pair' and 'other' in
entity 'Pair' cannot be inverse of each other because their types do
not form a valid combination.
Can anyone help me to understand the error and possibly fix it?
Thanks in advance, Lars
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[sqlalchemy] a more general elixir question
Is it possible to mix Elixir classes and SQLA classes in one database (with foreign keys between them)? Cheers, Lars -- 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: a more general elixir question
yes Elixir classes are in fact SQLA classes, only defined with a different syntax you can mix Elixir, Declarative and plain python objects mapped with SQLA On Feb 3, 12:13 pm, lars van gemerden l...@rational-it.com wrote: Is it possible to mix Elixir classes and SQLA classes in one database (with foreign keys between them)? Cheers, Lars -- 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: a more general elixir question
Thanks, Can you also mix Elixir Fields and SQLA Column/relationships in the same class? Cheers, Lars On Feb 3, 12:56 pm, erikj tw55...@gmail.com wrote: yes Elixir classes are in fact SQLA classes, only defined with a different syntax you can mix Elixir, Declarative and plain python objects mapped with SQLA On Feb 3, 12:13 pm, lars van gemerden l...@rational-it.com wrote: Is it possible to mix Elixir classes and SQLA classes in one database (with foreign keys between them)? Cheers, Lars -- 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: a more general elixir question
no, that's not possible Elixir does some custom postprocessing on a class definition, and so does Declarative, but they are not interoperatable On Feb 3, 1:20 pm, lars van gemerden l...@rational-it.com wrote: Thanks, Can you also mix Elixir Fields and SQLA Column/relationships in the same class? Cheers, Lars On Feb 3, 12:56 pm, erikj tw55...@gmail.com wrote: yes Elixir classes are in fact SQLA classes, only defined with a different syntax you can mix Elixir, Declarative and plain python objects mapped with SQLA On Feb 3, 12:13 pm, lars van gemerden l...@rational-it.com wrote: Is it possible to mix Elixir classes and SQLA classes in one database (with foreign keys between them)? Cheers, Lars -- 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: a more general elixir question
Too bad, thanks On Feb 3, 1:38 pm, erikj tw55...@gmail.com wrote: no, that's not possible Elixir does some custom postprocessing on a class definition, and so does Declarative, but they are not interoperatable On Feb 3, 1:20 pm, lars van gemerden l...@rational-it.com wrote: Thanks, Can you also mix Elixir Fields and SQLA Column/relationships in the same class? Cheers, Lars On Feb 3, 12:56 pm, erikj tw55...@gmail.com wrote: yes Elixir classes are in fact SQLA classes, only defined with a different syntax you can mix Elixir, Declarative and plain python objects mapped with SQLA On Feb 3, 12:13 pm, lars van gemerden l...@rational-it.com wrote: Is it possible to mix Elixir classes and SQLA classes in one database (with foreign keys between them)? Cheers, Lars -- 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] Having trouble getting a subquery to return entities
Hi:
I'm having trouble getting a subquery to return entities.
class Question(Base):
__tablename__ = 'question'
question_id = Column(INTEGER(unsigned=True), primary_key=True)
...etc
q_answers = relationship(Answer, backref=question)
class Answer(Base):
__tablename__ = 'answer'
answer_id = Column(INTEGER(unsigned=True), primary_key=True)
user_id = Column(INTEGER(unsigned=True), ForeignKey('user.user_id'),
nullable=False)
question_id = Column(INTEGER(unsigned=True),
ForeignKey('question.question_id'), nullable=False)
...etc
stmt = session.query(Answer).filter(Answer.user_id ==
user_id).subquery()
answers = aliased(Answer, stmt)
query = session.query(Question, answers)\
.outerjoin(answers, Question.q_answers)\
.filter(Question.question_group_id == question_group_id)
questions = query.all()
This generates MySQL that returns all desired columns and returns NULL
if question has not yet been answered by the specified user. Groovy so
far.
I was expecting tuples in the list of questions (Answer, Question),
but the first element is always None. e.g.
dir(questions[0])
[None, 'Question', ... etc
So while I'm expecting the subquery results to be understood as
entities (Answer), this isn't happening. But I cannot figure out why.
Where have I failed?
Thanks!
-C
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[sqlalchemy] Re: Having trouble getting a subquery to return entities
I should add: First element is always none _even if question has been
answered by that user_
On Feb 3, 11:28 am, cbc clayton.cafi...@mondaylambson.com wrote:
Hi:
I'm having trouble getting a subquery to return entities.
class Question(Base):
__tablename__ = 'question'
question_id = Column(INTEGER(unsigned=True), primary_key=True)
...etc
q_answers = relationship(Answer, backref=question)
class Answer(Base):
__tablename__ = 'answer'
answer_id = Column(INTEGER(unsigned=True), primary_key=True)
user_id = Column(INTEGER(unsigned=True), ForeignKey('user.user_id'),
nullable=False)
question_id = Column(INTEGER(unsigned=True),
ForeignKey('question.question_id'), nullable=False)
...etc
stmt = session.query(Answer).filter(Answer.user_id ==
user_id).subquery()
answers = aliased(Answer, stmt)
query = session.query(Question, answers)\
.outerjoin(answers, Question.q_answers)\
.filter(Question.question_group_id == question_group_id)
questions = query.all()
This generates MySQL that returns all desired columns and returns NULL
if question has not yet been answered by the specified user. Groovy so
far.
I was expecting tuples in the list of questions (Answer, Question),
but the first element is always None. e.g.
dir(questions[0])
[None, 'Question', ... etc
So while I'm expecting the subquery results to be understood as
entities (Answer), this isn't happening. But I cannot figure out why.
Where have I failed?
Thanks!
-C
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[sqlalchemy] update table record
Hi,
If i have a table named 'message' and it has the following columns:
message_id, tar_del, src_del. I pass in del_list which is a list of
message to delete. I tried the following
self.session.query(Message)\
.filter(Message.message_id.in_(del_list))\
.update({Message.tar_del: self._DELETE})
but kept getting this error
File /usr/lib64/python2.7/site-packages/sqlalchemy/orm/query.py,
line 2598, in update
Could not evaluate current criteria in Python.
InvalidRequestError: Could not evaluate current criteria in Python.
Specify 'fetch' or False for the synchronize_session parameter.
What does the error mean? What I ended up doing is
rows = self.session.query(Message)\
.filter(Message.message_id.in_(del_list))\
.all()
for r in rows:
if key == 'src_del'
r.src_del = self._DELETE
elif key == 'tar_del'
r.tar_del = self._DELETE
and just loop through the rows return, but I think this is not very
efficient.
Also, to reference a table column, I do r.src_del and r.tar_del, is it
possible to make it a variable, so I can do something like r[key] =
self._DELETE?
Thanks,
Mason
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[sqlalchemy] Using a standalone SEQUENCE
Is there an example or other explanation of how to use a SEQUENCE that is not a primary key on a table, particularly how to create the sequence, get next value, reset seq, etc. I see the base docs here, but it's not obvious to me how exactly to use this class. http://docs.sqlalchemy.org/en/latest/core/schema.html#sqlalchemy.schema.Sequence Thanks, Michael Hipp -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
Re: [sqlalchemy] Having trouble getting a subquery to return entities
On Feb 3, 2012, at 11:28 AM, cbc wrote:
Hi:
I'm having trouble getting a subquery to return entities.
class Question(Base):
__tablename__ = 'question'
question_id = Column(INTEGER(unsigned=True), primary_key=True)
...etc
q_answers = relationship(Answer, backref=question)
class Answer(Base):
__tablename__ = 'answer'
answer_id = Column(INTEGER(unsigned=True), primary_key=True)
user_id = Column(INTEGER(unsigned=True), ForeignKey('user.user_id'),
nullable=False)
question_id = Column(INTEGER(unsigned=True),
ForeignKey('question.question_id'), nullable=False)
...etc
stmt = session.query(Answer).filter(Answer.user_id ==
user_id).subquery()
answers = aliased(Answer, stmt)
query = session.query(Question, answers)\
.outerjoin(answers, Question.q_answers)\
.filter(Question.question_group_id == question_group_id)
questions = query.all()
This generates MySQL that returns all desired columns and returns NULL
if question has not yet been answered by the specified user. Groovy so
far.
I was expecting tuples in the list of questions (Answer, Question),
but the first element is always None. e.g.
dir(questions[0])
[None, 'Question', ... etc
So while I'm expecting the subquery results to be understood as
entities (Answer), this isn't happening. But I cannot figure out why.
Where have I failed?
The outerjoin here is from Question to Answer so you should never have None in
the first element of the tuple. I'd need a full reproducing test to see
exactly what would cause Question to be retuned as None.
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Re: [sqlalchemy] update table record
On Feb 3, 2012, at 1:04 PM, Mason wrote:
Hi,
If i have a table named 'message' and it has the following columns:
message_id, tar_del, src_del. I pass in del_list which is a list of
message to delete. I tried the following
self.session.query(Message)\
.filter(Message.message_id.in_(del_list))\
.update({Message.tar_del: self._DELETE})
but kept getting this error
File /usr/lib64/python2.7/site-packages/sqlalchemy/orm/query.py,
line 2598, in update
Could not evaluate current criteria in Python.
InvalidRequestError: Could not evaluate current criteria in Python.
Specify 'fetch' or False for the synchronize_session parameter.
the error message refers to the synchronize_session parameter of the update
method:
http://docs.sqlalchemy.org/en/latest/orm/query.html?highlight=query.update#sqlalchemy.orm.query.Query.update
pass False for this value instead of the default of evaluate:
query.update({Message.tar_del:self._DELETE}, synchronize_session=False)
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Re: [sqlalchemy] Using a standalone SEQUENCE
On Feb 3, 2012, at 6:24 PM, Michael Hipp wrote: Is there an example or other explanation of how to use a SEQUENCE that is not a primary key on a table, particularly how to create the sequence, get next value, reset seq, etc. I see the base docs here, but it's not obvious to me how exactly to use this class. http://docs.sqlalchemy.org/en/latest/core/schema.html#sqlalchemy.schema.Sequence the sequence is created on the Python side given a name: mysequence = Sequence(mysequence) so the docstrings list out create(), used as such: mysequence.create(engine) emits CREATE SEQUENCE and next_value(), returns a func element which can be executed: engine.execute(mysequence.next_value()) there's not a built in feature for RESET or other alterations of sequences right now, you'd have to execute() the appropriate SQL for your target backend. -- 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.
