On Fri, Mar 29, 2019 at 2:55 PM <ghlstd...@gmail.com> wrote:
>
> I have a model, Account, with two foreign keys / relationships to another
> model, Users.
>
> class Account(object):
> @declared_attr
> def customer_id(cls):
> return Column(ForeignKey(User.id))
> @declared_attr
> def customer(cls):
> return relationship(User, lazy='joined',
> foreign_keys=cls.customer_id)
>
> @declared_attr
> def reporter_id(cls):
> return Column(ForeignKey(User.id))
> @declared_attr
> def reporter(cls):
> return relationship(User, lazy='joined',
> foreign_keys=cls.reporter_id)
>
> session.query(Account) gives me the correct join logic for eager loading. The
> issue comes when I want to load this data into a pandas dataframe. The joined
> columns show up labeled as users_1_colname and users_2_colname which makes it
> unclear which came from reporter and which came from customer. I know in a
> one off query I can use aliases but how can I have a certain alias dedicated
> to a relationship? I don't want to manually generate the query and I don't
> want to change the column names in pandas. I want users_1 to always be
> labeled reporter and users_2 to always be labeled customer when I query
> Account. Is this possible?
When using relationships there is no exposure of any kind of "labels"
to the end user, unless you are taking the stringified version of an
ORM query using str(). There's no need to do that, as Query can
execute the results for you directly where it then returns them as ORM
objects, without you ever having to deal with any labels:
for acc in session.query(Account):
row = {"customer": acc.customer.name, "reporter":
acc.reporter.name} # or whatever fields you want, this assumes there
is a "User.name" field
my_dataframe.add_row(row) # or whatever pandas API is here
the names you use with the results of an ORM query that uses eager
loading are in terms of the attribute names you put on the objects.
There's a lot of other ways to do this, which can be more automatic,
but that's the simplest, feel free to share more details if this is
not sufficient.
>
> --
> 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.
