Question

I have a class mapped with a table, in my case in a declarative way, and I want to “discover” table properties, columns, names, relations, from this class:

engine = create_engine('sqlite:///' + databasePath, echo=True)

# setting up root class for declarative declaration
Base = declarative_base(bind=engine)

class Ship(Base):
    __tablename__ = 'ships'

    id = Column(Integer, primary_key=True)
    name = Column(String(255))

    def __init__(self, name):
            self.name = name

    def __repr__(self):
            return "<Ship('%s')>" % (self.name)

So now my goal is from the “Ship” class to get the table columns and their properties from another piece of code. I guess I can deal with it using instrumentation but is there any way provided by the SQLAlchemy API?

Answer 1

Information you need you can get from Table object:

• Ship.__table__.columns will provide you with columns information
• Ship.__table__.foreign_keys will list foreign keys
• Ship.__table__.constraints, Ship.__table__.indexes are other properties you might find useful