Thanks mike, that was a helpful explanation.
2017-03-06 18:59 GMT-03:00 mike bayer <mike...@zzzcomputing.com>: > > > On 03/06/2017 04:47 PM, Leonardo L. P. da Mata wrote: > >> Hello, thanks for the help. >> >> This makes sense but it looks like that the value is calculated twice, >> one in the query and the other accessing the property. >> >> My idea is to have the result on the query return itself. >> >> > "lat" and "lng" here are variables that are in your program and are not > related to the model you have. So you're asking that a particular object > be returned with additional values stuck onto it. > > The Session uses an identity map that ensures that an object of a > particular primary key is only present once; if you make two queries which > both return the same primary key, you get the same object back. > > If you did two queries with different values of "lat" / "lng" that both > ultimately return the same PartnerAddress object, would the old values be > erased? It's not clear. > > Instead, this "distance" you're getting is really a value associated not > just with the object but this specific query. You can get it back by just > adding it as a column: > > query = session.query(PartnerV3, PartnerAddress.distance(lat, > lng)).join(PartnerAddress).order_by(PartnerAddress.distance(lat, lng)) > > > for partnerv3, distance in query: > print distance > > > > >> >> 2017-03-06 18:31 GMT-03:00 mike bayer <mike...@zzzcomputing.com >> <mailto:mike...@zzzcomputing.com>>: >> >> >> >> On 03/06/2017 04:16 PM, Leonardo Mata wrote: >> >> Hello, My applications does some ordering using the distance from >> latitude and longitude haversine distance, i was able to >> calculate this >> using @hybrid.method and @.*expression, but i can't output the >> calculated distance: >> >> /class PartnerAddress(db.Model, WithTimestampsModel, >> SerializeMixin):/ >> / / >> / # Columns/ >> / id = db.Column(db.Integer(), primary_key=True, >> nullable=False)/ >> / >> / >> / partner_id = db.Column(/ >> / db.Integer(),/ >> / db.ForeignKey('partner.id <http://partner.id>'),/ >> / nullable=False/ >> / )/ >> / >> / >> / latitude = db.Column(db.Numeric(precision=9, scale=7), >> nullable=False)/ >> / longitude = db.Column(db.Numeric(precision=10, scale=7), >> nullable=False)/ >> / / >> / >> / >> / @hybrid_method/ >> / def distance(self, lat, lng):/ >> / / >> / return math.acos(math.cos(math.radians(self.latitude)) * >> math.cos(math.radians(lat)) */ >> / math.cos(math.radians(self.longitude) - >> math.radians(lng)) +/ >> / math.sin(math.radians(self.la >> <http://self.la>titude)) * >> >> math.sin(math.radians(lat))) * 6371/ >> / >> / >> / @distance.expression/ >> / def distance(cls, lat, lng):/ >> / return func.acos(func.cos(func.radians(cls.latitude)) * >> func.cos(func.radians(lat)) */ >> / func.cos(func.radians(lng) - >> func.radians(cls.longitude)) +/ >> / func.sin(func.radians(cls.latitude)) * >> func.sin(func.radians(lat))) * 6371/ >> / >> / >> / >> / >> /class PartnerV3(db.Model, WithTimestampsModel,/ >> / SoftDeletableModel, SerializeMixin):/ >> / / >> / >> / >> / name = db.Column(db.String(128), nullable=False)/ >> / / >> / >> / >> / address = db.relationship(/ >> / 'mustafar.partner.v3.models.ad >> <http://mustafar.partner.v3.models.ad>dress.PartnerAddress',/ >> >> / backref='partner',/ >> / uselist=False/ >> / )/ >> >> >> when querying like this: >> >> query = >> PartnerV3.query.join(PartnerAddress).order_by(PartnerAddress >> .distance(lat, >> lng)).paginate(1,10, False) >> >> I can paginate the result, but it returns only the PartnerV3 >> object, i >> can't access the distance. >> >> How do I access this distance property? >> >> >> you have a PartnerV3 there so the PartnerAddress is on the .address >> property: >> >> query = >> PartnerV3.query.join(PartnerAddress).order_by(PartnerAddress >> .distance(lat, >> lng)) >> >> >> some_partner = query.first() >> >> partner_address = some_partner.address >> distance = partner_address.distance(lat, lng) >> >> >> >> >> >> >> >> >> >> >> -- >> 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 >> <http://stackoverflow.com/help/mcve> for a full >> description. >> --- >> You received this message because you are subscribed to the Google >> Groups "sqlalchemy" group. >> To unsubscribe from this group and stop receiving emails from >> it, send >> an email to sqlalchemy+unsubscr...@googlegroups.com >> <mailto:sqlalchemy%2bunsubscr...@googlegroups.com> >> <mailto:sqlalchemy+unsubscr...@googlegroups.com >> <mailto:sqlalchemy%2bunsubscr...@googlegroups.com>>. >> To post to this group, send email to sqlalchemy@googlegroups.com >> <mailto:sqlalchemy@googlegroups.com> >> <mailto:sqlalchemy@googlegroups.com >> <mailto:sqlalchemy@googlegroups.com>>. >> Visit this group at https://groups.google.com/group/sqlalchemy >> <https://groups.google.com/group/sqlalchemy>. >> For more options, visit https://groups.google.com/d/optout >> <https://groups.google.com/d/optout>. >> >> >> -- >> 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 >> <http://stackoverflow.com/help/mcve> for a full description. >> --- You received this message because you are subscribed to a topic >> in the Google Groups "sqlalchemy" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/sqlalchemy/4JKV8vS4jis/unsubscribe >> <https://groups.google.com/d/topic/sqlalchemy/4JKV8vS4jis/unsubscribe >> >. >> To unsubscribe from this group and all its topics, send an email to >> sqlalchemy+unsubscr...@googlegroups.com >> <mailto:sqlalchemy%2bunsubscr...@googlegroups.com>. >> To post to this group, send email to sqlalchemy@googlegroups.com >> <mailto:sqlalchemy@googlegroups.com>. >> Visit this group at https://groups.google.com/group/sqlalchemy >> <https://groups.google.com/group/sqlalchemy>. >> For more options, visit https://groups.google.com/d/optout >> <https://groups.google.com/d/optout>. >> >> >> >> >> -- >> Leonardo Luiz Padovani da Mata >> barr...@gmail.com <mailto:barr...@gmail.com> >> >> "May the force be with you, always" >> "Nerd Pride... eu tenho. Voce tem?" >> >> -- >> 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. >> --- >> You received this message because you are subscribed to the Google >> Groups "sqlalchemy" group. >> To unsubscribe from this group and stop receiving emails from it, send >> an email to sqlalchemy+unsubscr...@googlegroups.com >> <mailto:sqlalchemy+unsubscr...@googlegroups.com>. >> To post to this group, send email to sqlalchemy@googlegroups.com >> <mailto:sqlalchemy@googlegroups.com>. >> Visit this group at https://groups.google.com/group/sqlalchemy. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > 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. > --- You received this message because you are subscribed to a topic in the > Google Groups "sqlalchemy" group. > To unsubscribe from this topic, visit https://groups.google.com/d/to > pic/sqlalchemy/4JKV8vS4jis/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > sqlalchemy+unsubscr...@googlegroups.com. > To post to this group, send email to sqlalchemy@googlegroups.com. > Visit this group at https://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. > -- Leonardo Luiz Padovani da Mata barr...@gmail.com "May the force be with you, always" "Nerd Pride... eu tenho. Voce tem?" -- 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. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
