I've added theses lines here
<https://bitbucket.org/zzzeek/sqlalchemy/src/c7d6c667b53d96a65e0dedcb83c098e03d4c7453/lib/sqlalchemy/ext/automap.py?at=master&fileviewer=file-view-default#automap.py-953>
:
if relationship_name in map_config.properties:
msg = "%s relationship name conflict: %s" % (
local_cls.__name__, relationship_name)
util.warn(msg)
and it produces warnings as excepted :
>>> from dbmodels import *
/usr/local/lib/python2.7/dist-packages/sqlalchemy/ext/automap.py:961:
SAWarning: *thermostats relationship name conflict: dispositif_ref*
util.warn(msg)
Whats wrong with this approach ? Is there any case that overwrite
relationship_name in map_config.properties is correct ?
Le dimanche 3 janvier 2016 19:09:04 UTC+2, Michael Bayer a écrit :
>
>
>
> On 01/03/2016 07:00 AM, [email protected] <javascript:> wrote:
> > OK, thanks you.
> >
> > I think it's a good idea to issue a warning in such cases.
>
> unfortunately this is a difficult situation to detect since it is a
> valid use case to present a mapped class that already has relationships
> present on it, which will not be overridden. Additional bookkeeping
> would need to be added to the automap process to track all those class/
> name combinations that were locally added without coming up with false
> positives.
>
>
>
> >
> > Best regards
> >
> > Le samedi 2 janvier 2016 19:18:12 UTC+2, Michael Bayer a écrit :
> >
> >
> >
> > On 01/02/2016 11:38 AM, [email protected] <javascript:> wrote:
> > > Thank you.
> > >
> > > I hesitate between using this way, or explicitly specify the
> > relationship
> > > (is this a good idea? In my test I found 3 relations after
> > prepare()) :
> >
> > it's fine to do that. Automap is still building its own
> > relationship as
> > well which is why you end up with three of them. The
> > generate_relationship hook can be used to return None in those cases
> > where you don't want automap to generate a relationship:
> >
> http://docs.sqlalchemy.org/en/rel_1_0/orm/extensions/automap.html#sqlalchemy.ext.automap.generate_relationship
>
> > <
> http://docs.sqlalchemy.org/en/rel_1_0/orm/extensions/automap.html#sqlalchemy.ext.automap.generate_relationship>
>
>
> >
> >
> >
> > >
> > > |
> > > classThermostat(Base):
> > > __tablename__ ='thermostats'
> > > idbuiltin =Column(Integer,ForeignKey('device.id
> > <http://device.id>'))
> > > idthermometer =Column(Integer,ForeignKey('device.id
> > <http://device.id>'))
> > > thermometer
> =relationship(Dispositif,foreign_keys=idthermometer)
> > > builtin =relationship(Dispositif,foreign_keys=idbuiltin)
> > > |
> > >
> > >
> > > Another interesting point is how to detect this error to warn. I
> > tried
> > > to use name_for_scalar_relationship() for that, but I don't kow
> > how to
> > > get the relationships mapper.
> > >
> > > Best regards
> > >
> > > Le vendredi 1 janvier 2016 18:27:14 UTC+2, Michael Bayer a écrit :
> > >
> > > you need to use the name generation functions
> > > name_for_scalar_relationship() and/or
> > > name_for_collection_relationship()
> > > to produce different names in each case. The "constraint"
> > parameter
> > > passed as we see in
> > >
> >
> http://docs.sqlalchemy.org/en/rel_1_0/orm/extensions/automap.html#handling-simple-naming-conflicts
>
> > <
> http://docs.sqlalchemy.org/en/rel_1_0/orm/extensions/automap.html#handling-simple-naming-conflicts>
>
>
> >
> > >
> > <
> http://docs.sqlalchemy.org/en/rel_1_0/orm/extensions/automap.html#handling-simple-naming-conflicts
>
> > <
> http://docs.sqlalchemy.org/en/rel_1_0/orm/extensions/automap.html#handling-simple-naming-conflicts>>
>
>
> >
> > >
> > > is a ForeignKeyConstraint object, you can look inside of
> > > constraint.column_keys to see if it is ['idbuiltin'] or
> > > ['idthermometer'] and use that to generate a name.
> > >
> > >
> > >
> > > On 01/01/2016 04:16 AM, [email protected] <javascript:>
> wrote:
> > > > Hi all,
> > > >
> > > > I use automap with database reflection to import schema with
> > > sqlalchemy.
> > > >
> > > > In case I have two relationships on same foreign key in some
> > > table, only
> > > > one relationship is created by prepare(), the second one
> seems
> > > overwrited.
> > > >
> > > > My table looks like :
> > > >
> > > > |
> > > > Table('thermostat',
> > > > Base.metadata,
> > > > Column('id',INTEGER(),primary_key=True,nullable=False),
> > > > Column('idbuiltin',INTEGER(),ForeignKey('device.id
> > <http://device.id>
> > > <http://device.id>')),
> > > > Column('idthermometer',INTEGER(),ForeignKey('device.id
> > <http://device.id>
> > > <http://device.id>')))
> > > > |
> > > >
> > > > How to control relationship creation to produce two distinct
> > > relationships ?
> > > >
> > > > Thank you and Happy New Year !
> > > >
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