title: flask-sqlalchemy give empty result from database view
body: <p>I have Model:</p>
  
  <pre><code>from flask.ext.sqlalchemy import SQLAlchemy 
  db = SQLAlchemy()
  class Graph(db.Model):
      __tablename__ = 'graph_view'
      group = Column(Unicode(250), primary_key=True)
      port_id1 = Column('portid1', Integer)
      port_id2 = Column('portid2', Integer)
      equipment_id1 = Column('equipmentid1', Integer)
      equipment_id2 = Column('equipmentid2', Integer)
  </code></pre>
  
  <p>where graph_view is database view. I am doing SELECT after connect:</p>
  
  <pre><code>    Graph.query.all()
  </code></pre>
  
  <p>and i'm getting nothing. Query is not wrong what can i do to fix this?</p>