I meant, do the query only when email is required, and not unless anything else is required. if I call merge(), the query is instantly emitted. I want it to be emitted only if an unloaded attribute is requested.
On Friday, 2 March 2018 11:51:20 UTC-5, Mike Bayer wrote: > > On Fri, Mar 2, 2018 at 11:30 AM, Harshvardhan Gupta > <harsh...@gmail.com <javascript:>> wrote: > > There is no way to achieve what I want without doing the query? > > merge seems to do the whole query. > > you have a User row, and you want to load columns in that row, like > "full_name". How would you like to achieve that without emitting a > 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> 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. > >> > 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.
