title: sqlalchemy : How does Base know that i have defined a class mapped to it?
body: <p>It just works when I simply do an inheritance with my class</p>
  
  <pre><code>class User(Base):
      __tablename__ = ’users’
      id = Column(Integer, primary_key=True)
      name = Column(String)
      fullname = Column(String)
      password = Column(String)
  </code></pre>
  
  <p>And then i'm able to create the table using <code>Base.metadata.create_all(engine)</code></p>
  
  <p>My question is, how can sqlalchemy know that i have already defined User (inherited from Base) ?</p>