hi there,
I have a proble defining my relations.

I have thwo tables that are linked in a m:n relation using an association table
This works fine.

Now the problematic part:
each entry in the association table takes part in a m:n relationship to any number of companies

This I can not do.

here are the involved tables:

------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------

class tblCompany(Base2):
    __table__ = tables2['tblCompany']


# services
from sqlalchemy import Table
tblServiceTechnologyCompetence_has_tblCompany = Table('tblServiceTechnologyCompetence_has_tblCompany', Base2.metadata, autoload=True)

# technology tells us what technology like hybridkollektoren or Niedertemperatursystem we are
# dealing with
class tblServiceTechnology(Base2):
    __table__ = tables2["tblServiceTechnology"]

# category  Kategorie wie Wärmeerzeugung, HLWDt
class tblServiceCategory(Base2):
    __table__ = tables2["tblServiceCategory"]
    # backref to the company
    technologies = relationship(
        tblServiceTechnology,
        backref = backref('category')
    )

# we have a m:n relationship between
# tblServiceTechnologyCompetence and tblServiceTechnology
# each such relationship has a m:n relationship to companies
class tblServiceTechnology_has_Competence(Base2):
    __table__ = tables2["tblServiceTechnology_has_Competence"]
    #backref to the company
    companies = relationship(
        'tblCompany',
        secondary=tblServiceTechnologyCompetence_has_tblCompany,
        backref="competences",
    )

# competence tells us what competence like Systemanbieter, Herstellung, Planung within a technology
# some entity is offering
class tblServiceTechnologyCompetence(Base2):
    __table__ = tables2["tblServiceTechnologyCompetence"]
    technologies = relationship(
        "tblServiceTechnology",
        secondary="tblServiceTechnology_has_Competence",
        backref = 'competences'
    )

------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------
now I get the error:

AttributeError: type object 'tblServiceTechnology_has_Competence' has no attribute 'foreign_keys'

I tried also:

class tblServiceTechnologyCompetence(Base2):
    __table__ = tables2["tblServiceTechnologyCompetence"]
    technologies = relationship(
        tblServiceTechnology,
        secondary=tblServiceTechnology_has_Competence,

primaryjoin="tblServiceTechnology_has_Competence.idcompetence_comp_comp==tblServiceTechnologyCompetence.id",

secondaryjoin="tblServiceTechnology_has_Competence.idtechnology_comp_comp==tblServiceTechnology.id",
    )

then the error I get is:
AttributeError: 'tblServiceTechnology_has_Competence' object has no attribute 'c'


how should I define such a relationship.

thanks for your time
robert

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