Python sqlalchemy.orm.synonym() Examples

def setup_classes(cls):
        from sqlalchemy.orm import synonym

        Base = cls.DeclarativeBasic

        class A(Base):
            __tablename__ = "a"

            id = Column(Integer, primary_key=True)
            data = Column(String)
            bs = relationship("B", backref="a")
            data_syn = synonym("data")

            b_data = association_proxy("bs", "data_syn")

        class B(Base):
            __tablename__ = "b"
            id = Column(Integer, primary_key=True)
            a_id = Column(ForeignKey("a.id"))
            data = Column(String)
            data_syn = synonym("data")

            a_data = association_proxy("a", "data_syn") 

def test_proxy_descriptor_one(self):
        class Point(object):
            def __init__(self, x, y):
                self.x, self.y = x, y

        self._fixture(Point, properties={"x_syn": synonym("x")})
        alias = aliased(Point)

        eq_(str(Point.x_syn), "Point.x_syn")
        eq_(str(alias.x_syn), "AliasedClass_Point.x_syn")

        sess = Session()
        self.assert_compile(
            sess.query(alias.x_syn).filter(alias.x_syn > Point.x_syn),
            "SELECT point_1.x AS point_1_x FROM point AS point_1, point "
            "WHERE point_1.x > point.x",
        ) 

def test_synonym(self):
        users = self.tables.users

        class User(object):
            def _getValue(self):
                return self._value

            def _setValue(self, value):
                setattr(self, "_value", value)

            value = property(_getValue, _setValue)

        mapper(User, users, properties={"uid": synonym("id")})

        sess = create_session()
        u = User()
        u.name = "ed"
        sess.add(u)
        sess.flush()
        sess.expunge(u)
        sess.merge(u) 

def test_synonym_nonexistent_attr(self):
        # test [ticket:4767].
        # synonym points to non-existent attrbute that hasn't been mapped yet.
        users = self.tables.users

        class User(object):
            def _x(self):
                return self.id

            x = property(_x)

        m = mapper(
            User,
            users,
            properties={"x": synonym("some_attr", descriptor=User.x)},
        )

        # object gracefully handles this condition
        assert not hasattr(User.x, "__name__")
        assert not hasattr(User.x, "comparator")

        m.add_property("some_attr", column_property(users.c.name))

        assert not hasattr(User.x, "__name__")
        assert hasattr(User.x, "comparator") 

def test_info(self):
        users = self.tables.users
        Address = self.classes.Address

        class MyComposite(object):
            pass

        for constructor, args in [
            (column_property, (users.c.name,)),
            (relationship, (Address,)),
            (composite, (MyComposite, "id", "name")),
            (synonym, "foo"),
        ]:
            obj = constructor(info={"x": "y"}, *args)
            eq_(obj.info, {"x": "y"})
            obj.info["q"] = "p"
            eq_(obj.info, {"x": "y", "q": "p"})

            obj = constructor(*args)
            eq_(obj.info, {})
            obj.info["q"] = "p"
            eq_(obj.info, {"q": "p"}) 

def test_column_prefix(self):
        users, User = self.tables.users, self.classes.User

        mapper(
            User,
            users,
            column_prefix="_",
            properties={"user_name": synonym("_name")},
        )

        s = create_session()
        u = s.query(User).get(7)
        eq_(u._name, "jack")
        eq_(u._id, 7)
        u2 = s.query(User).filter_by(user_name="jack").one()
        assert u is u2 

def test_evaluate_double_synonym_attr(self):
        class Foo(object):
            pass

        mapper(
            Foo,
            self.tables.users,
            properties={"uname": synonym("name"), "ufoo": synonym("uname")},
        )

        s = Session()
        jill = s.query(Foo).get(3)
        s.query(Foo).update(
            {Foo.ufoo: "moonbeam"}, synchronize_session="evaluate"
        )
        eq_(jill.ufoo, "moonbeam") 

def test_synonym_column_location(self):
        users, User = self.tables.users, self.classes.User

        def go():
            mapper(
                User,
                users,
                properties={"not_name": synonym("_name", map_column=True)},
            )

        assert_raises_message(
            sa.exc.ArgumentError,
            (
                "Can't compile synonym '_name': no column on table "
                "'users' named 'not_name'"
            ),
            go,
        ) 

def test_synonym_options(self):
        Address, addresses, users, User = (
            self.classes.Address,
            self.tables.addresses,
            self.tables.users,
            self.classes.User,
        )

        mapper(
            User,
            users,
            properties=dict(
                addresses=relationship(
                    mapper(Address, addresses),
                    lazy="select",
                    order_by=addresses.c.id,
                ),
                adlist=synonym("addresses"),
            ),
        )

        def go():
            sess = create_session()
            u = (
                sess.query(User)
                .order_by(User.id)
                .options(sa.orm.joinedload("adlist"))
                .filter_by(name="jack")
            ).one()
            eq_(u.adlist, [self.static.user_address_result[0].addresses[0]])

        self.assert_sql_count(testing.db, go, 1) 

def test_synonym_of_synonym(self):
        users, User = (self.tables.users, self.classes.User)

        mapper(User, users, properties={"x": synonym("id"), "y": synonym("x")})

        s = Session()
        u = s.query(User).filter(User.y == 8).one()
        eq_(u.y, 8) 

def test_synonym_get_history(self):
        users, User = (self.tables.users, self.classes.User)

        mapper(User, users, properties={"x": synonym("id"), "y": synonym("x")})

        u1 = User()
        eq_(attributes.instance_state(u1).attrs.x.history, (None, None, None))
        eq_(attributes.instance_state(u1).attrs.y.history, (None, None, None))

        u1.y = 5
        eq_(attributes.instance_state(u1).attrs.x.history, ([5], (), ()))
        eq_(attributes.instance_state(u1).attrs.y.history, ([5], (), ())) 

def test_synonym_map_column_conflict(self):
        users, User = self.tables.users, self.classes.User

        assert_raises(
            sa.exc.ArgumentError,
            mapper,
            User,
            users,
            properties=util.OrderedDict(
                [
                    ("_user_id", users.c.id),
                    ("id", synonym("_user_id", map_column=True)),
                ]
            ),
        )

        assert_raises(
            sa.exc.ArgumentError,
            mapper,
            User,
            users,
            properties=util.OrderedDict(
                [
                    ("id", synonym("_user_id", map_column=True)),
                    ("_user_id", users.c.id),
                ]
            ),
        ) 

def test_self_ref_synonym(self):
        t = Table(
            "nodes",
            MetaData(),
            Column(
                "id", Integer, primary_key=True, test_needs_autoincrement=True
            ),
            Column("parent_id", Integer, ForeignKey("nodes.id")),
        )

        class Node(object):
            pass

        mapper(
            Node,
            t,
            properties={
                "_children": relationship(
                    Node, backref=backref("_parent", remote_side=t.c.id)
                ),
                "children": synonym("_children"),
                "parent": synonym("_parent"),
            },
        )

        n1 = Node()
        n2 = Node()
        n1.children.append(n2)
        assert n2.parent is n2._parent is n1
        assert n1.children[0] is n1._children[0] is n2
        eq_(str(Node.parent == n2), ":param_1 = nodes.parent_id") 

def test_synonym(self):
        users, User = self.tables.users, self.classes.User

        from sqlalchemy.orm.properties import ColumnProperty

        class MyFactory(ColumnProperty.Comparator):
            __hash__ = None

            def __eq__(self, other):
                return func.foobar(self.__clause_element__()) == func.foobar(
                    other
                )

        mapper(
            User,
            users,
            properties={
                "name": synonym(
                    "_name", map_column=True, comparator_factory=MyFactory
                )
            },
        )
        self.assert_compile(
            User.name == "ed",
            "foobar(users.name) = foobar(:foobar_1)",
            dialect=default.DefaultDialect(),
        )

        self.assert_compile(
            aliased(User).name == "ed",
            "foobar(users_1.name) = foobar(:foobar_1)",
            dialect=default.DefaultDialect(),
        ) 

def setup_mappers(cls):
        cls._setup_stock_mapping()
        inspect(cls.classes.User).add_property("name_syn", synonym("name")) 

def test_synonym_fk(self):
        """test that active history is enabled on a
        one-to-many/one that has use_get==True"""

        tableB, A, B, tableA = (
            self.tables.tableB,
            self.classes.A,
            self.classes.B,
            self.tables.tableA,
        )

        mapper(
            B, tableB, properties={"a_id": synonym("_a_id", map_column=True)}
        )
        mapper(
            A,
            tableA,
            properties={
                "b": relationship(
                    B,
                    primaryjoin=(tableA.c.id == foreign(B.a_id)),
                    uselist=False,
                )
            },
        )

        sess = create_session()

        b = B(id=0)
        a = A(id=0, b=b)
        sess.add(a)
        sess.add(b)
        sess.flush()
        sess.expunge_all()

        assert a.b == b
        assert a.id == b.a_id
        assert a.id == b._a_id 

def tenant_id(cls):
        return orm.synonym(
            'project_id',
            descriptor=property(cls.get_tenant_id, cls.set_tenant_id)) 

def state(self):
        return synonym('_state', descriptor=property(self.get_state, self.set_state)) 

def test_synonym_replaces_backref(self):
        addresses, users, User = (
            self.tables.addresses,
            self.tables.users,
            self.classes.User,
        )

        assert_calls = []

        class Address(object):
            def _get_user(self):
                assert_calls.append("get")
                return self._user

            def _set_user(self, user):
                assert_calls.append("set")
                self._user = user

            user = property(_get_user, _set_user)

        # synonym is created against nonexistent prop
        mapper(Address, addresses, properties={"user": synonym("_user")})
        sa.orm.configure_mappers()

        # later, backref sets up the prop
        mapper(
            User,
            users,
            properties={"addresses": relationship(Address, backref="_user")},
        )

        sess = create_session()
        u1 = sess.query(User).get(7)
        u2 = sess.query(User).get(8)
        # comparaison ops need to work
        a1 = sess.query(Address).filter(Address.user == u1).one()
        eq_(a1.id, 1)
        a1.user = u2
        assert a1.user is u2
        eq_(assert_calls, ["set", "get"]) 

def test_evaluate_synonym_attr(self):
        class Foo(object):
            pass

        mapper(Foo, self.tables.users, properties={"uname": synonym("name")})

        s = Session()
        jill = s.query(Foo).get(3)
        s.query(Foo).update(
            {Foo.uname: "moonbeam"}, synchronize_session="evaluate"
        )
        eq_(jill.uname, "moonbeam") 

def setup_mappers(cls):
        User = cls.classes.User
        Address = cls.classes.Address
        users, addresses = (cls.tables.users, cls.tables.addresses)
        mapper(
            User,
            users,
            properties={
                "addresses": relationship(Address),
                "ad_syn": synonym("addresses"),
            },
        )
        mapper(Address, addresses) 

def test_polymorphic_synonym(self):
        class T1(fixtures.ComparableEntity):
            def info(self):
                return "THE INFO IS:" + self._info

            def _set_info(self, x):
                self._info = x

            info = property(info, _set_info)

        class T2(T1):
            pass

        mapper(
            T1,
            t1,
            polymorphic_on=t1.c.type,
            polymorphic_identity="t1",
            properties={"info": synonym("_info", map_column=True)},
        )
        mapper(T2, t2, inherits=T1, polymorphic_identity="t2")
        sess = create_session()
        at1 = T1(info="at1")
        at2 = T2(info="at2", data="t2 data")
        sess.add(at1)
        sess.add(at2)
        sess.flush()
        sess.expunge_all()
        eq_(sess.query(T2).filter(T2.info == "at2").one(), at2)
        eq_(at2.info, "THE INFO IS:at2") 

def test_polymorphic_on_synonym(self):
        t1 = self.tables.t1
        Parent = self.classes.Parent
        cprop = column_property(t1.c.x)
        assert_raises_message(
            sa_exc.ArgumentError,
            "Only direct column-mapped property or "
            "SQL expression can be passed for polymorphic_on",
            mapper,
            Parent,
            t1,
            properties={"discriminator": cprop, "discrim_syn": synonym(cprop)},
            polymorphic_identity="parent",
            polymorphic_on="discrim_syn",
        ) 

def test_add_property(self):
        users = self.tables.users

        assert_col = []

        class User(fixtures.ComparableEntity):
            def _get_name(self):
                assert_col.append(("get", self._name))
                return self._name

            def _set_name(self, name):
                assert_col.append(("set", name))
                self._name = name

            name = property(_get_name, _set_name)

        m = mapper(User, users)

        m.add_property("_name", deferred(users.c.name))
        m.add_property("name", synonym("_name"))

        sess = create_session(autocommit=False)
        assert sess.query(User).get(7)

        u = sess.query(User).filter_by(name="jack").one()

        def go():
            eq_(u.name, "jack")
            eq_(assert_col, [("get", "jack")], str(assert_col))

        self.sql_count_(1, go) 

def test_synonym_group_bug(self):
        orders, Order = self.tables.orders, self.classes.Order

        mapper(
            Order,
            orders,
            properties={
                "isopen": synonym("_isopen", map_column=True),
                "description": deferred(orders.c.description, group="foo"),
            },
        )

        sess = create_session()
        o1 = sess.query(Order).get(1)
        eq_(o1.description, "order 1") 

def answer(self):
        """The answer. Could be the same as main_answer in simple cases.

        This property is the most useful representation available of the
        answer. In the simplest case it is just a synonym for main_answer.
        It could otherwise be a dictionary or another model.
        """ 

def val(cls):   # pylint: disable=no-self-argument
        """
        Get Airflow Variable from Metadata DB and decode it using the Fernet Key
        """
        return synonym('_val', descriptor=property(cls.get_val, cls.set_val)) 

def extra(cls):   # pylint: disable=no-self-argument
        """Extra data. The value is decrypted/encrypted when reading/setting the value."""
        return synonym('_extra',
                       descriptor=property(cls.get_extra, cls.set_extra)) 

def password(cls):   # pylint: disable=no-self-argument
        """Password. The value is decrypted/encrypted when reading/setting the value."""
        return synonym('_password',
                       descriptor=property(cls.get_password, cls.set_password)) 

def test_add_property(self):
        users, addresses, Address = (
            self.tables.users,
            self.tables.addresses,
            self.classes.Address,
        )

        assert_col = []

        class User(fixtures.ComparableEntity):
            def _get_name(self):
                assert_col.append(("get", self._name))
                return self._name

            def _set_name(self, name):
                assert_col.append(("set", name))
                self._name = name

            name = property(_get_name, _set_name)

        m = mapper(User, users)
        mapper(Address, addresses)

        m.add_property("_name", deferred(users.c.name))
        m.add_property("name", synonym("_name"))
        m.add_property("addresses", relationship(Address))

        sess = create_session(autocommit=False)
        assert sess.query(User).get(7)

        u = sess.query(User).filter_by(name="jack").one()

        def go():
            eq_(
                len(u.addresses),
                len(self.static.user_address_result[0].addresses),
            )
            eq_(u.name, "jack")
            eq_(assert_col, [("get", "jack")], str(assert_col))

        self.sql_count_(2, go)

        u.name = "ed"
        u3 = User()
        u3.name = "some user"
        sess.add(u3)
        sess.flush()
        sess.rollback()