title: SQLAlchemy: How to properly use Relationship()?
body: <p>I went through the docs, and <strong>think</strong> I've structured everything correctly, but struggling to implement it. </p>
  
  <p>There's two pieces to this: The use case is when I look at a resume, each resume has multiple jobs. Then the sum of all of those jobs determines the value of the entire resume. </p>
  
  <p>I've set up two tables &amp; corresponding classes. </p>
  
  <pre><code>from sqlalchemy import Column, Integer, String
  from sqlalchemy import create_engine
  from sqlalchemy.ext.declarative import declarative_base
  from sqlalchemy.orm import sessionmaker
  from sqlalchemy.orm import relationship
  from sqlalchemy import ForeignKey
  
  Base = declarative_base()
  engine = create_engine('sqlite:///candidate.db', echo=True)
  
  
  class Candidate_Evaluation(Base):
      __tablename__ = 'candidate_evaluation'
      id = Column(Integer, primary_key=True)
      label = Column(String)
      url = Column(String)
      string_of_job_evals = Column(String)
      job_evaluation_relationship = relationship("Job_Evaluation", back_populates="candidate_evalution")
      def __repr__(self):
          "&lt;Candidate(URL = '%s', label = '%s', job evaluations = '%s')&gt;" % (self.url, self.label, self.string_of_job_evals)
  
  
  class Job_Evaluation(Base):
      __tablename__ = 'job_evaluation'
      id = Column(Integer, primary_key=True)
      candidate_evaluation_id = Column(Integer, ForeignKey('candidate_evaluation.id')) #
      details = Column(String)
      label = Column(String)
      candidate_evaluation_relationship = relationship("Candidate_Evaluation", back_populates='job_evaluation')
      def __repr__(self):
          "&lt;Job(label = '%s', details = '%s')&gt;" %(self.label, self.details)
  
  
  Base.metadata.create_all(engine)
  Session = sessionmaker(bind=engine)
  session = Session()
  
  job = Job_Evaluation(label = 'front_end', details = 'javascript jquery html css')
  session.add(job)
  session.commit()
  </code></pre>
  
  <p>However, I'm running into a problem when I try to add records to the <code>job_evaluation</code> table. I <strong>think</strong> it has to do with how I've set up the relationship between them.</p>
  
  <p>The goal is that I can add job evaluation to the database and then link it to the candidate evaluation. It's a Many to One relationship, but the Many comes first. Is that possible? </p>
  
  <p>I'm getting the error: </p>
  
  <p><code>sqlalchemy.exc.InvalidRequestError: Mapper 'Mapper|Job_Evaluation|job_evaluation' has no property 'candidate_evalution'</code></p>
  
  <p>What am I doing wrong?</p>