There is no way to achieve what I want without doing the query? merge seems to do the whole query. I also have asked this question on stack overflow which talks about my use case :
https://stackoverflow.com/questions/49062520/querying-properties-of-transient-models-in-sqlalchemy On Friday, 2 March 2018 11:27:31 UTC-5, Mike Bayer wrote: > > On Fri, Mar 2, 2018 at 11:21 AM, Harshvardhan Gupta > <harsh...@gmail.com <javascript:>> wrote: > > I also tried loading a related attribute , and it still returns None. > > > you need to merge the object: > > my_user = session.merge(my_user) > > that is your only option. E.g. do the query. > > > > > > > On Friday, 2 March 2018 11:00:47 UTC-5, Harshvardhan Gupta wrote: > >> > >> Thanks, I am able to call my object, but the attribute prints none: > >> > >> > >> E.g. my model is: > >> > >> class User(Dictifiable, db.Model, UserMixin): > >> __tablename__ = 'user' > >> > >> id = Column(Integer, Sequence('user_id_seq'), primary_key=True) > >> full_name = Column(String(50)) > >> > >> > >> And this is what I have done : > >> > >> `u_lazy = User(id=1)` > >> `db.session().enable_relationship_loading(u_lazy)` > >> when i try to print u_lazy.full_name, it shows null (it is non null in > db > >> ) > >> > >> > >> On Friday, 2 March 2018 10:55:11 UTC-5, Mike Bayer wrote: > >>> > >>> On Fri, Mar 2, 2018 at 10:52 AM, Harshvardhan Gupta > >>> <harsh...@gmail.com> wrote: > >>> > Thanks for the reply. > >>> > > >>> > There is a guarantee that the user will exist ,why is why I want to > >>> > prevent that extra db query. > >>> > > >>> > When I try to do enable relationship loading ,I get the error : > >>> > Scoped session has no attribute enable relationship loading. > >>> > >>> that's a scoped_session(), not a Session, access the Session by > >>> calling it: scoped_session().enable_relationship_loading(obj) > >>> > >>> > > >>> > -- > >>> > 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+...@googlegroups.com. > >>> > To post to this group, send email to sqlal...@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 the Google > Groups > > "sqlalchemy" group. > > To unsubscribe from this group and stop receiving emails from it, send > an > > email to sqlalchemy+...@googlegroups.com <javascript:>. > > To post to this group, send email to sqlal...@googlegroups.com > <javascript:>. > > 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 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.
