Python orm.create_session函数代码示例

    def test_dontload_with_backrefs(self):
        """dontload populates relations in both directions without requiring a load"""
        mapper(User, users, properties={
            'addresses':relation(mapper(Address, addresses), backref='user')
        })

        u = User(id=7, name='fred', addresses=[
            Address(email_address='ad1'),
            Address(email_address='ad2')])
        sess = create_session()
        sess.add(u)
        sess.flush()
        sess.close()
        assert 'user' in u.addresses[1].__dict__

        sess = create_session()
        u2 = sess.merge(u, dont_load=True)
        assert 'user' in u2.addresses[1].__dict__
        eq_(u2.addresses[1].user, User(id=7, name='fred'))

        sess.expire(u2.addresses[1], ['user'])
        assert 'user' not in u2.addresses[1].__dict__
        sess.close()

        sess = create_session()
        u = sess.merge(u2, dont_load=True)
        assert 'user' not in u.addresses[1].__dict__
        eq_(u.addresses[1].user, User(id=7, name='fred'))

    def test_class_deferred_cols(self):
        mapper(User, users, properties={
            'name':sa.orm.deferred(users.c.name),
            'addresses':relation(Address, backref="user")
        })
        mapper(Address, addresses, properties={
            'email_address':sa.orm.deferred(addresses.c.email_address)
        })
        sess = create_session()
        u1 = User(name='ed')
        u1.addresses.append(Address(email_address='[email protected]'))
        sess.add(u1)
        sess.flush()
        sess.clear()
        u1 = sess.query(User).get(u1.id)
        assert 'name' not in u1.__dict__
        assert 'addresses' not in u1.__dict__

        u2 = pickle.loads(pickle.dumps(u1))
        sess2 = create_session()
        sess2.update(u2)
        self.assertEquals(u2.name, 'ed')
        self.assertEquals(u2, User(name='ed', addresses=[Address(email_address='[email protected]')]))

        u2 = pickle.loads(pickle.dumps(u1))
        sess2 = create_session()
        u2 = sess2.merge(u2, dont_load=True)
        self.assertEquals(u2.name, 'ed')
        self.assertEquals(u2, User(name='ed', addresses=[Address(email_address='[email protected]')]))

    def test_dontload_with_eager(self):
        """

        This test illustrates that with dont_load=True, we can't just copy the
        committed_state of the merged instance over; since it references
        collection objects which themselves are to be merged.  This
        committed_state would instead need to be piecemeal 'converted' to
        represent the correct objects.  However, at the moment I'd rather not
        support this use case; if you are merging with dont_load=True, you're
        typically dealing with caching and the merged objects shouldnt be
        'dirty'.

        """
        mapper(User, users, properties={
            'addresses':relation(mapper(Address, addresses))
        })
        sess = create_session()
        u = User()
        u.id = 7
        u.name = "fred"
        a1 = Address()
        a1.email_address='[email protected]'
        u.addresses.append(a1)

        sess.add(u)
        sess.flush()

        sess2 = create_session()
        u2 = sess2.query(User).options(sa.orm.eagerload('addresses')).get(7)

        sess3 = create_session()
        u3 = sess3.merge(u2, dont_load=True)
        def go():
            sess3.flush()
        self.assert_sql_count(testing.db, go, 0)

    def test_one_to_one_cascade(self):

        mapper(User, users, properties={
            'address':relation(mapper(Address, addresses),uselist = False)
        })
        on_load = self.on_load_tracker(User)
        self.on_load_tracker(Address, on_load)
        sess = create_session()

        u = User()
        u.id = 7
        u.name = "fred"
        a1 = Address()
        a1.email_address='[email protected]'
        u.address = a1

        sess.add(u)
        sess.flush()

        eq_(on_load.called, 0)

        sess2 = create_session()
        u2 = sess2.query(User).get(7)
        eq_(on_load.called, 1)
        u2.name = 'fred2'
        u2.address.email_address = '[email protected]'
        eq_(on_load.called, 2)

        u3 = sess.merge(u2)
        eq_(on_load.called, 2)
        assert u3 is u

    def test_reentrant_compile_via_foreignkey(self):
        class User(Base, ComparableEntity):
            __tablename__ = 'users'

            id = Column('id', Integer, primary_key=True)
            name = Column('name', String(50))
            addresses = relation("Address", backref="user")

        class Address(Base, ComparableEntity):
            __tablename__ = 'addresses'

            id = Column('id', Integer, primary_key=True)
            email = Column('email', String(50))
            user_id = Column('user_id', Integer, ForeignKey(User.id))

        # this forces a re-entrant compile() due to the User.id within the
        # ForeignKey
        sa.orm.compile_mappers()

        Base.metadata.create_all()
        u1 = User(name='u1', addresses=[
            Address(email='one'),
            Address(email='two'),
        ])
        sess = create_session()
        sess.add(u1)
        sess.flush()
        sess.clear()

        eq_(sess.query(User).all(), [User(name='u1', addresses=[
            Address(email='one'),
            Address(email='two'),
        ])])

    def test_order_by_multi(self):
        class Address(Base, ComparableEntity):
            __tablename__ = 'addresses'

            id = Column('id', Integer, primary_key=True)
            email = Column('email', String(50))
            user_id = Column('user_id', Integer, ForeignKey('users.id'))

        class User(Base, ComparableEntity):
            __tablename__ = 'users'

            id = Column('id', Integer, primary_key=True)
            name = Column('name', String(50))
            addresses = relation("Address", order_by=(Address.email, Address.id))

        Base.metadata.create_all()
        u1 = User(name='u1', addresses=[
            Address(email='two'),
            Address(email='one'),
        ])
        sess = create_session()
        sess.add(u1)
        sess.flush()
        sess.clear()
        u = sess.query(User).filter(User.name == 'u1').one()
        a = u.addresses

    def test_as_declarative(self):
        class User(ComparableEntity):
            __tablename__ = 'users'

            id = Column('id', Integer, primary_key=True)
            name = Column('name', String(50))
            addresses = relation("Address", backref="user")

        class Address(ComparableEntity):
            __tablename__ = 'addresses'

            id = Column('id', Integer, primary_key=True)
            email = Column('email', String(50))
            user_id = Column('user_id', Integer, ForeignKey('users.id'))
        
        reg = {}
        decl.instrument_declarative(User, reg, Base.metadata)
        decl.instrument_declarative(Address, reg, Base.metadata)
        Base.metadata.create_all()
        
        u1 = User(name='u1', addresses=[
            Address(email='one'),
            Address(email='two'),
        ])
        sess = create_session()
        sess.add(u1)
        sess.flush()
        sess.clear()

        eq_(sess.query(User).all(), [User(name='u1', addresses=[
            Address(email='one'),
            Address(email='two'),
        ])])

 def test_one_to_many_scalar(self):
     mapper(User, users, properties = dict(
         address = relation(mapper(Address, addresses), lazy=True, uselist=False)
     ))
     q = create_session().query(User)
     l = q.filter(users.c.id == 7).all()
     assert [User(id=7, address=Address(id=1))] == l

    def test_eager_order_by(self):
        class Address(Base, ComparableEntity):
            __tablename__ = 'addresses'

            id = Column('id', Integer, primary_key=True)
            email = Column('email', String(50))
            user_id = Column('user_id', Integer, ForeignKey('users.id'))

        class User(Base, ComparableEntity):
            __tablename__ = 'users'

            id = Column('id', Integer, primary_key=True)
            name = Column('name', String(50))
            addresses = relation("Address", order_by=Address.email)

        Base.metadata.create_all()
        u1 = User(name='u1', addresses=[
            Address(email='two'),
            Address(email='one'),
        ])
        sess = create_session()
        sess.add(u1)
        sess.flush()
        sess.clear()
        eq_(sess.query(User).options(eagerload(User.addresses)).all(), [User(name='u1', addresses=[
            Address(email='one'),
            Address(email='two'),
        ])])

    def test_basic(self):
        meta = MetaData(testing.db)

        class User(Base, ComparableEntity):
            __tablename__ = 'users'
            __autoload__ = True
            addresses = relation("Address", backref="user")

        class Address(Base, ComparableEntity):
            __tablename__ = 'addresses'
            __autoload__ = True

        u1 = User(name='u1', addresses=[
            Address(email='one'),
            Address(email='two'),
            ])
        sess = create_session()
        sess.add(u1)
        sess.flush()
        sess.clear()

        eq_(sess.query(User).all(), [User(name='u1', addresses=[
            Address(email='one'),
            Address(email='two'),
            ])])

        a1 = sess.query(Address).filter(Address.email == 'two').one()
        eq_(a1, Address(email='two'))
        eq_(a1.user, User(name='u1'))

    def test_detached_to_persistent_collection(self):
        mapper(User, users, properties={
            'addresses':relation(Address,
                                 backref='user',
                                 collection_class=OrderedSet)})
        mapper(Address, addresses)
        on_load = self.on_load_tracker(User)
        self.on_load_tracker(Address, on_load)

        a = Address(id=1, email_address='fred1')
        u = User(id=7, name='fred', addresses=OrderedSet([
            a,
            Address(id=2, email_address='fred2'),
        ]))
        sess = create_session()
        sess.add(u)
        sess.flush()
        sess.clear()

        u.name='fred jones'
        u.addresses.add(Address(id=3, email_address='fred3'))
        u.addresses.remove(a)

        eq_(on_load.called, 0)
        u = sess.merge(u)
        eq_(on_load.called, 4)
        sess.flush()
        sess.clear()

        eq_(sess.query(User).first(),
            User(id=7, name='fred jones', addresses=OrderedSet([
                Address(id=2, email_address='fred2'),
                Address(id=3, email_address='fred3')])))

    def test_compileonattr_rel_backref_b(self):
        m = MetaData()
        t1 = Table("t1", m, Column("id", Integer, primary_key=True), Column("x", Integer))
        t2 = Table("t2", m, Column("id", Integer, primary_key=True), Column("t1_id", Integer, ForeignKey("t1.id")))

        class Base(object):
            def __init__(self):
                pass

        class Base_AKW(object):
            def __init__(self, *args, **kwargs):
                pass

        for base in object, Base, Base_AKW:

            class A(base):
                pass

            class B(base):
                pass

            mapper(A, t1)
            mapper(B, t2, properties=dict(a=relation(A, backref="bs")))

            a = A()
            b = B()
            b.a = a

            session = create_session()
            session.add(a)
            assert b in session, "base: %s" % base

    def test_expired_eager(self):
        mapper(User, users, properties={
            'addresses':relation(Address, backref='user', lazy=False),
            })
        mapper(Address, addresses)

        sess = create_session()
        u = sess.query(User).get(7)

        sess.expire(u)
        assert 'name' not in u.__dict__
        assert 'addresses' not in u.__dict__

        def go():
            assert u.addresses[0].email_address == '[email protected]'
            assert u.name == 'jack'
        # two loads, since relation() + scalar are
        # separate right now on per-attribute load
        self.assert_sql_count(testing.db, go, 2)
        assert 'name' in u.__dict__
        assert 'addresses' in u.__dict__

        sess.expire(u, ['name', 'addresses'])
        assert 'name' not in u.__dict__
        assert 'addresses' not in u.__dict__

        def go():
            sess.query(User).filter_by(id=7).one()
            assert u.addresses[0].email_address == '[email protected]'
            assert u.name == 'jack'
        # one load, since relation() + scalar are
        # together when eager load used with Query
        self.assert_sql_count(testing.db, go, 1)

    def test_basic(self):
        mapper(Employee, employees)
        mapper(Department, departments, properties=dict(employees=relation(Employee, lazy=False, backref="department")))

        d1 = Department(name="One")
        for e in "Jim", "Jack", "John", "Susan":
            d1.employees.append(Employee(name=e))

        d2 = Department(name="Two")
        for e in "Joe", "Bob", "Mary", "Wally":
            d2.employees.append(Employee(name=e))

        sess = create_session()
        sess.add_all((d1, d2))
        sess.flush()

        q = (
            sess.query(Department)
            .join("employees")
            .filter(Employee.name.startswith("J"))
            .distinct()
            .order_by([sa.desc(Department.name)])
        )

        eq_(q.count(), 2)
        assert q[0] is d2

    def testone(self):
        """
        Tests eager load of a many-to-one attached to a one-to-many.  this
        testcase illustrated the bug, which is that when the single Company is
        loaded, no further processing of the rows occurred in order to load
        the Company's second Address object.

        """
        mapper(Address, addresses)

        mapper(Company, companies, properties={"addresses": relation(Address, lazy=False)})

        mapper(Invoice, invoices, properties={"company": relation(Company, lazy=False)})

        a1 = Address(address="a1 address")
        a2 = Address(address="a2 address")
        c1 = Company(company_name="company 1", addresses=[a1, a2])
        i1 = Invoice(date=datetime.datetime.now(), company=c1)

        session = create_session()
        session.add(i1)
        session.flush()

        company_id = c1.company_id
        invoice_id = i1.invoice_id

        session.clear()
        c = session.query(Company).get(company_id)

        session.clear()
        i = session.query(Invoice).get(invoice_id)

        eq_(c, i.company)