please add an answer to your stackoverflow question as well
On Fri, Mar 2, 2018 at 11:55 AM, Mike Bayer <mike...@zzzcomputing.com> wrote:
> On Fri, Mar 2, 2018 at 11:55 AM, Harshvardhan Gupta
> <harshsay...@gmail.com> wrote:
>> 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.
>
> make the object act like detached and expired, then associate with the
> session:
>
> from sqlalchemy.orm.session import make_transient_to_detached
> a1 = A(id=1)
> make_transient_to_detached(a1)
> s.add(a1)
>
> print("-------------------")
> assert a1.data == "some data"
> assert len(a1.bs) == 3
>
>
>
>
>
>>
>> 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> 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.
>>> > 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+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.
--
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.
