title: SQLAlchemy Session.add doesn't work?
body: <p>I have a strange error using Python 3.3.0 and SQLAlchemy 0.8.0:</p>
  
  <pre><code>from sqlalchemy import create_engine, Integer, String, Text, Column, Sequence, DateTime, ForeignKey
  from sqlalchemy.orm import sessionmaker, relationship, backref
  from sqlalchemy.ext.declarative import declarative_base
  
  engine = create_engine("sqlite:///:memory:", echo=True)
  Session = sessionmaker(bind = engine)
  Base = declarative_base()
  
  class Product(Base):
      __tablename__ = "products"
  
      id = Column(Integer, primary_key=True)
      name = Column(String(200))
      description = Column(Text)
  
  Base.metadata.create_all(engine)
  
  session = Session()
  product = Product()
  product.id = 1
  product.name = "Test"
  product.description = "Test"
  
  session.add(product)
  print(product in session) # Expected true
  session.commit()
  print(session.query(Product).all()) # Expected the previous item
  </code></pre>
  
  <p>As commented in code I expected the add method to add the product to the database using an INSERT. But it doesn't nor does it throw an exception. This is the log:</p>
  
  <pre><code>2013-04-16 18:03:14,368 INFO sqlalchemy.engine.base.Engine PRAGMA table_info("products")
  2013-04-16 18:03:14,369 INFO sqlalchemy.engine.base.Engine ()
  2013-04-16 18:03:14,371 INFO sqlalchemy.engine.base.Engine 
  CREATE TABLE products (
      id INTEGER NOT NULL, 
      name VARCHAR(200), 
      description TEXT, 
      PRIMARY KEY (id)
  )
  
  
  2013-04-16 18:03:14,371 INFO sqlalchemy.engine.base.Engine ()
  2013-04-16 18:03:14,371 INFO sqlalchemy.engine.base.Engine COMMIT
  False
  2013-04-16 18:04:04,706 INFO sqlalchemy.engine.base.Engine BEGIN (implicit)
  2013-04-16 18:04:04,708 INFO sqlalchemy.engine.base.Engine SELECT products.id AS products_id, products.name AS products_name, products.description AS products_description 
  FROM products
  2013-04-16 18:04:04,709 INFO sqlalchemy.engine.base.Engine ()
  []
  </code></pre>
  
  <p>I already tried several things: </p>
  
  <ul>
  <li>Changing the engine doesn't work. I also tried postgresql. </li>
  <li>I tried debugging. When I reach the body of the add method there is nothing to step into.</li>
  </ul>
  
  <p>Am I doing something wrong or is this a bug?</p>