1 files changed, 127 insertions, 72 deletions
diff --git a/examples/inheritance/single.py b/examples/inheritance/single.py
index 22a6fe027..56397f540 100644
--- a/examples/inheritance/single.py
+++ b/examples/inheritance/single.py
@@ -1,102 +1,157 @@
-"""Single-table inheritance example."""
-
-from sqlalchemy import MetaData, Table, Column, Integer, String, \
-    ForeignKey, create_engine
-from sqlalchemy.orm import mapper, relationship, sessionmaker
-
-metadata = MetaData()
-
-# a table to store companies
-companies = Table('companies', metadata,
-   Column('company_id', Integer, primary_key=True),
-   Column('name', String(50)))
-
-employees_table = Table('employees', metadata,
-    Column('employee_id', Integer, primary_key=True),
-    Column('company_id', Integer, ForeignKey('companies.company_id')),
-    Column('name', String(50)),
-    Column('type', String(20)),
-    Column('status', String(20)),
-    Column('engineer_name', String(50)),
-    Column('primary_language', String(50)),
-    Column('manager_name', String(50))
-)
+"""Single-table (table-per-hierarchy) inheritance example."""
+
+from sqlalchemy import Column, Integer, String, \
+    ForeignKey, create_engine, inspect, or_
+from sqlalchemy.orm import relationship, Session, with_polymorphic
+from sqlalchemy.ext.declarative import declarative_base, declared_attr
+
+Base = declarative_base()
+
 
+class Company(Base):
+    __tablename__ = 'company'
+    id = Column(Integer, primary_key=True)
+    name = Column(String(50))
+
+    employees = relationship(
+        "Person",
+        back_populates='company',
+        cascade='all, delete-orphan')
+
+    def __repr__(self):
+        return "Company %s" % self.name
+
+
+class Person(Base):
+    __tablename__ = 'person'
+    id = Column(Integer, primary_key=True)
+    company_id = Column(ForeignKey('company.id'))
+    name = Column(String(50))
+    type = Column(String(50))
+
+    company = relationship("Company", back_populates="employees")
+
+    __mapper_args__ = {
+        'polymorphic_identity': 'person',
+        'polymorphic_on': type
+    }
 
-class Person(object):
-    def __init__(self, **kwargs):
-        for key, value in kwargs.items():
-            setattr(self, key, value)
     def __repr__(self):
         return "Ordinary person %s" % self.name
+
+
 class Engineer(Person):
-    def __repr__(self):
-        return "Engineer %s, status %s, engineer_name %s, "\
-                    "primary_language %s" % \
-                        (self.name, self.status,
-                        self.engineer_name, self.primary_language)
-class Manager(Person):
-    def __repr__(self):
-        return "Manager %s, status %s, manager_name %s" % \
-                    (self.name, self.status, self.manager_name)
-class Company(object):
-    def __init__(self, **kwargs):
-        for key, value in kwargs.items():
-            setattr(self, key, value)
-    def __repr__(self):
-        return "Company %s" % self.name
 
-person_mapper = mapper(Person, employees_table,
-                       polymorphic_on=employees_table.c.type,
-                       polymorphic_identity='person')
-manager_mapper = mapper(Manager, inherits=person_mapper,
-                        polymorphic_identity='manager')
-engineer_mapper = mapper(Engineer, inherits=person_mapper,
-                         polymorphic_identity='engineer')
+    engineer_name = Column(String(30))
+    primary_language = Column(String(30))
 
-mapper(Company, companies, properties={
-    'employees': relationship(Person, lazy=True, backref='company')
-})
+    # illustrate a single-inh "conflicting" column declaration;
+    # see http://docs.sqlalchemy.org/en/latest/orm/extensions/
+    #       declarative/inheritance.html#resolving-column-conflicts
+    @declared_attr
+    def status(cls):
+        return Person.__table__.c.get('status', Column(String(30)))
 
+    __mapper_args__ = {
+        'polymorphic_identity': 'engineer',
+    }
 
-engine = create_engine('sqlite:///', echo=True)
+    def __repr__(self):
+        return (
+            "Engineer %s, status %s, engineer_name %s, "
+            "primary_language %s" %
+            (
+                self.name, self.status,
+                self.engineer_name, self.primary_language)
+        )
+
+
+class Manager(Person):
+    manager_name = Column(String(30))
 
-metadata.create_all(engine)
+    @declared_attr
+    def status(cls):
+        return Person.__table__.c.get('status', Column(String(30)))
 
-session = sessionmaker(engine)()
+    __mapper_args__ = {
+        'polymorphic_identity': 'manager',
+    }
 
-c = Company(name='company1')
-c.employees.append(Manager(name='pointy haired boss', status='AAB',
-                   manager_name='manager1'))
-c.employees.append(Engineer(name='dilbert', status='BBA',
-                   engineer_name='engineer1', primary_language='java'))
-c.employees.append(Person(name='joesmith', status='HHH'))
-c.employees.append(Engineer(name='wally', status='CGG',
-                   engineer_name='engineer2', primary_language='python'
-                   ))
-c.employees.append(Manager(name='jsmith', status='ABA',
-                   manager_name='manager2'))
+    def __repr__(self):
+        return "Manager %s, status %s, manager_name %s" % (
+            self.name, self.status, self.manager_name)
+
+
+engine = create_engine('sqlite://', echo=True)
+Base.metadata.create_all(engine)
+
+session = Session(engine)
+
+c = Company(name='company1', employees=[
+    Manager(
+        name='pointy haired boss',
+        status='AAB',
+        manager_name='manager1'),
+    Engineer(
+        name='dilbert',
+        status='BBA',
+        engineer_name='engineer1',
+        primary_language='java'),
+    Person(name='joesmith'),
+    Engineer(
+        name='wally',
+        status='CGG',
+        engineer_name='engineer2',
+        primary_language='python'),
+    Manager(
+        name='jsmith',
+        status='ABA',
+        manager_name='manager2')
+])
 session.add(c)
+
 session.commit()
 
 c = session.query(Company).get(1)
 for e in c.employees:
-    print(e, e.company)
-
+    print(e, inspect(e).key, e.company)
+assert set([e.name for e in c.employees]) == set(
+    ['pointy haired boss', 'dilbert', 'joesmith', 'wally', 'jsmith'])
 print("\n")
 
 dilbert = session.query(Person).filter_by(name='dilbert').one()
 dilbert2 = session.query(Engineer).filter_by(name='dilbert').one()
 assert dilbert is dilbert2
 
-dilbert.engineer_name = 'hes dibert!'
+dilbert.engineer_name = 'hes dilbert!'
 
-session.flush()
-session.expunge_all()
+session.commit()
 
 c = session.query(Company).get(1)
 for e in c.employees:
     print(e)
 
-session.delete(c)
+# query using with_polymorphic.
+eng_manager = with_polymorphic(Person, [Engineer, Manager])
+print(
+    session.query(eng_manager).
+    filter(
+        or_(
+            eng_manager.Engineer.engineer_name == 'engineer1',
+            eng_manager.Manager.manager_name == 'manager2'
+        )
+    ).all()
+)
+
+# illustrate join from Company,
+eng_manager = with_polymorphic(Person, [Engineer, Manager])
+print(
+    session.query(Company).
+    join(
+        Company.employees.of_type(eng_manager)
+    ).filter(
+        or_(eng_manager.Engineer.engineer_name == 'engineer1',
+            eng_manager.Manager.manager_name == 'manager2')
+    ).all())
+
 session.commit()