python - Get attribute of object from relationship in sqlalchemy -

consider following code defining classes:

from sqlalchemy.ext.declarative import declarative_base sqlalchemy import column, integer, float, string, datetime sqlalchemy import foreignkey, uniqueconstraint sqlalchemy.orm import relationship, backref  class base(object):     id = column(integer, primary_key=true) base = declarative_base(cls=base)  class teacher(base):     __tablename__ = 'teacher'      email = column(string, unique=true)     name = column(string, nullable=false)     password = column(string)     base_score = column(float)     time_zone = column(string)      def __repr__(self):         return '<teacher({0})>'.format(self.email)  class class(base):     __tablename__ = 'class'      teacher_id = column(integer, foreignkey('teacher.id', ondelete="cascade"), nullable=false, index=true)     teacher = relationship("teacher", backref=backref('classes', order_by='class.id'))     name = column(string, index=true)      __table_args__ = (uniqueconstraint('teacher_id','name'),)      def __repr__(self):         return '<class({0})>'.format(self.name)  class student(base):     __tablename__ = 'student'      class_id = column(integer, foreignkey('class.id', ondelete="cascade"), nullable=false, index=true)     class = relationship("class", backref=backref('students', order_by='student.id'))     name = column(string, index=true)      __table_args__ = (uniqueconstraint('class_id','name'),)      def __repr__(self):         return '<student({0})>'.format(self.name) 

and following code using classes:

from sqlalchemy import create_engine sqlalchemy.orm import sessionmaker  engine = create_engine('sqlite:///:memory:', echo=true)  base.metadata.create_all(engine) session = sessionmaker(bind=engine) session = session()  t = teacher(email='test@example.com',name='cool guy',base_score=100,time_zone='america/chicago')  c1 = class(teacher=t,name='mathematics') s1 = student(class=c1,name='bob roberts') 

first of all, want know if defining c1 right way (using teacher argument.)

second of all, know if can teacher of student doing:

s1.class.teacher 

but there anyway ( , normal) create teacher attribute directly on student class? tried adding:

teacher = class.teacher 

in class definition, threw:

attributeerror: 'relationshipproperty' object has no attribute 'teacher' 

obviously, it's not big of deal, want know correct way (if there one, or there not one) i'm trying learn sqlalchemy better.

so discovered answer second question... do

@property def teacher(self):     return self.class.teacher 

this generic python classes (new-style think.)

now

s1.class.teacher 

returns teacher object.

edit: since no 1 else has answered question, , code works how think should, i'm going coded correct way (in reference question 1.)