Re: [sqlalchemy] Querying using objects
Thanks Mike! I just did that :) And is a pretty, simple and reusable
comparator for me.
Cheers,
Richard.
On 04/17/2013 04:56 PM, Michael Bayer wrote:
OK, if you want to stick with hybrids, you can define your own
"SomeClass.myattribute == someobject" behavior by creating your own
comparator, see the docs at
http://docs.sqlalchemy.org/en/rel_0_8/orm/extensions/hybrid.html#building-custom-comparators
.
On Apr 17, 2013, at 7:15 AM, Richard Gerd Kuesters
mailto:rich...@humantech.com.br>> wrote:
Thank you Mike!
In fact, that's not my actual model - it is a little more complex
than that (specially the @setter), that's why my curiosity about
using hybrids and the possibility to query against an object.
Best regards,
Richard.
On 04/16/2013 09:34 PM, Michael Bayer wrote:
On Apr 16, 2013, at 9:30 AM, Richard Gerd Kuesters
mailto:rich...@humantech.com.br>> wrote:
Hello all!
Ok, maybe people asks this a lot, but I wonder if it's possible to
perform a query using an object as a filter - and I searched for
it, didn't found anything close to my idea.
Simple dumb example code:
*class User(Base):**
**
** user_id = Column(Integer, Sequence(...), primary_key=True)**
** username = Column(Unicode)**
**
**
**class Subscription(Base):**
**
**subscription_id = Column(Integer, Sequence(...),
primary_key=True)**
**name = Column(unicode)**
**owner_id = Column(Integer, ForeignKey('user.user_id'),
nullable=False)**
**
**@hybrid_property**
**def owner(self):**
if not object_session(self):
return None
**return
object_session(self).query(User).filter(self.owner_id ==
User.user_id)**.first()
**
**@owner.setter**
**def owner(self, owner):**
**self.owner_id = owner.user_id if isinstance(owner, User)
else owner**
**if object_session(self):**
**object_session(self).commit()**
**
**# @owner.expression**# ???**
**
**
**# ok, so far *almost* good**
*
OK, all of that complexity with hybrid_property is not needed at all
here. Just say, "owner = relationship("User")", and you're done.
SQLAlchemy manages one-to-many, many-to-one, and many-to-many
automatically with relationship().
*
**
**# but, i would like to do _this_ instead**
**
**print session.query(Subscription).filter(Subscription.owner ==
new_user).all()*
I've tried it in so many ways that I feel dizzy. The only way I
think would be using @owner.expression to "return User", but that
didn't the trick, it only appends "WHERE false" to the query, hehehe.
yeah just use relationship(), and you'd be using the first operator
as described right here in the ORM tutorial (which is a must-read):
http://docs.sqlalchemy.org/en/rel_0_8/orm/tutorial.html#common-relationship-operators
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Re: [sqlalchemy] Querying using objects
OK, if you want to stick with hybrids, you can define your own
"SomeClass.myattribute == someobject" behavior by creating your own comparator,
see the docs at
http://docs.sqlalchemy.org/en/rel_0_8/orm/extensions/hybrid.html#building-custom-comparators
.
On Apr 17, 2013, at 7:15 AM, Richard Gerd Kuesters
wrote:
> Thank you Mike!
>
> In fact, that's not my actual model - it is a little more complex than that
> (specially the @setter), that's why my curiosity about using hybrids and the
> possibility to query against an object.
>
>
> Best regards,
> Richard.
>
> On 04/16/2013 09:34 PM, Michael Bayer wrote:
>>
>> On Apr 16, 2013, at 9:30 AM, Richard Gerd Kuesters
>> wrote:
>>
>>> Hello all!
>>>
>>> Ok, maybe people asks this a lot, but I wonder if it's possible to perform
>>> a query using an object as a filter - and I searched for it, didn't found
>>> anything close to my idea.
>>>
>>> Simple dumb example code:
>>>
>>>
>>> class User(Base):
>>>
>>> user_id = Column(Integer, Sequence(...), primary_key=True)
>>> username = Column(Unicode)
>>>
>>>
>>> class Subscription(Base):
>>>
>>> subscription_id = Column(Integer, Sequence(...), primary_key=True)
>>> name = Column(unicode)
>>> owner_id = Column(Integer, ForeignKey('user.user_id'), nullable=False)
>>>
>>> @hybrid_property
>>> def owner(self):
>>> if not object_session(self):
>>> return None
>>> return object_session(self).query(User).filter(self.owner_id ==
>>> User.user_id).first()
>>>
>>> @owner.setter
>>> def owner(self, owner):
>>> self.owner_id = owner.user_id if isinstance(owner, User) else owner
>>> if object_session(self):
>>> object_session(self).commit()
>>>
>>> # @owner.expression # ???
>>>
>>>
>>> # ok, so far *almost* good
>>
>> OK, all of that complexity with hybrid_property is not needed at all here.
>> Just say, "owner = relationship("User")", and you're done. SQLAlchemy
>> manages one-to-many, many-to-one, and many-to-many automatically with
>> relationship().
>>
>>>
>>>
>>> # but, i would like to do _this_ instead
>>>
>>> print session.query(Subscription).filter(Subscription.owner ==
>>> new_user).all()
>>>
>>>
>>> I've tried it in so many ways that I feel dizzy. The only way I think would
>>> be using @owner.expression to "return User", but that didn't the trick, it
>>> only appends "WHERE false" to the query, hehehe.
>>
>> yeah just use relationship(), and you'd be using the first operator as
>> described right here in the ORM tutorial (which is a must-read):
>> http://docs.sqlalchemy.org/en/rel_0_8/orm/tutorial.html#common-relationship-operators
>>
>>
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>> email to sqlalchemy+unsubscr...@googlegroups.com.
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>>
>>
>
>
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Re: [sqlalchemy] Querying using objects
Thank you Mike!
In fact, that's not my actual model - it is a little more complex than
that (specially the @setter), that's why my curiosity about using
hybrids and the possibility to query against an object.
Best regards,
Richard.
On 04/16/2013 09:34 PM, Michael Bayer wrote:
On Apr 16, 2013, at 9:30 AM, Richard Gerd Kuesters
mailto:rich...@humantech.com.br>> wrote:
Hello all!
Ok, maybe people asks this a lot, but I wonder if it's possible to
perform a query using an object as a filter - and I searched for it,
didn't found anything close to my idea.
Simple dumb example code:
*class User(Base):**
**
** user_id = Column(Integer, Sequence(...), primary_key=True)**
** username = Column(Unicode)**
**
**
**class Subscription(Base):**
**
**subscription_id = Column(Integer, Sequence(...),
primary_key=True)**
**name = Column(unicode)**
**owner_id = Column(Integer, ForeignKey('user.user_id'),
nullable=False)**
**
**@hybrid_property**
**def owner(self):**
if not object_session(self):
return None
**return
object_session(self).query(User).filter(self.owner_id ==
User.user_id)**.first()
**
**@owner.setter**
**def owner(self, owner):**
**self.owner_id = owner.user_id if isinstance(owner, User)
else owner**
**if object_session(self):**
**object_session(self).commit()**
**
**# @owner.expression** # ???**
**
**
**# ok, so far *almost* good**
*
OK, all of that complexity with hybrid_property is not needed at all
here. Just say, "owner = relationship("User")", and you're done.
SQLAlchemy manages one-to-many, many-to-one, and many-to-many
automatically with relationship().
*
**
**# but, i would like to do _this_ instead**
**
**print session.query(Subscription).filter(Subscription.owner ==
new_user).all()*
I've tried it in so many ways that I feel dizzy. The only way I think
would be using @owner.expression to "return User", but that didn't
the trick, it only appends "WHERE false" to the query, hehehe.
yeah just use relationship(), and you'd be using the first operator as
described right here in the ORM tutorial (which is a must-read):
http://docs.sqlalchemy.org/en/rel_0_8/orm/tutorial.html#common-relationship-operators
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Re: [sqlalchemy] Querying using objects
On Apr 16, 2013, at 9:30 AM, Richard Gerd Kuesters
wrote:
> Hello all!
>
> Ok, maybe people asks this a lot, but I wonder if it's possible to perform a
> query using an object as a filter - and I searched for it, didn't found
> anything close to my idea.
>
> Simple dumb example code:
>
>
> class User(Base):
>
> user_id = Column(Integer, Sequence(...), primary_key=True)
> username = Column(Unicode)
>
>
> class Subscription(Base):
>
> subscription_id = Column(Integer, Sequence(...), primary_key=True)
> name = Column(unicode)
> owner_id = Column(Integer, ForeignKey('user.user_id'), nullable=False)
>
> @hybrid_property
> def owner(self):
> if not object_session(self):
> return None
> return object_session(self).query(User).filter(self.owner_id ==
> User.user_id).first()
>
> @owner.setter
> def owner(self, owner):
> self.owner_id = owner.user_id if isinstance(owner, User) else owner
> if object_session(self):
> object_session(self).commit()
>
> # @owner.expression # ???
>
>
> # ok, so far *almost* good
OK, all of that complexity with hybrid_property is not needed at all here.
Just say, "owner = relationship("User")", and you're done. SQLAlchemy manages
one-to-many, many-to-one, and many-to-many automatically with relationship().
>
>
> # but, i would like to do _this_ instead
>
> print session.query(Subscription).filter(Subscription.owner == new_user).all()
>
>
> I've tried it in so many ways that I feel dizzy. The only way I think would
> be using @owner.expression to "return User", but that didn't the trick, it
> only appends "WHERE false" to the query, hehehe.
yeah just use relationship(), and you'd be using the first operator as
described right here in the ORM tutorial (which is a must-read):
http://docs.sqlalchemy.org/en/rel_0_8/orm/tutorial.html#common-relationship-operators
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