mirror of
https://github.com/sqlalchemy/sqlalchemy.git
synced 2026-05-13 04:07:20 -04:00
Mike Bayer
67 lines
1.9 KiB
Python
67 lines
1.9 KiB
Python
from sqlalchemy import *
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from sqlalchemy.orm import *
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metadata = MetaData()
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managers_table = Table('managers', metadata,
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Column('employee_id', Integer, primary_key=True),
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Column('name', String(50)),
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Column('manager_data', String(40))
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)
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engineers_table = Table('engineers', metadata,
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Column('employee_id', Integer, primary_key=True),
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Column('name', String(50)),
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Column('engineer_info', String(40))
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)
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engine = create_engine('sqlite:///', echo=True)
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metadata.create_all(engine)
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class Employee(object):
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def __init__(self, name):
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self.name = name
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def __repr__(self):
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return self.__class__.__name__ + " " + self.name
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class Manager(Employee):
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def __init__(self, name, manager_data):
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self.name = name
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self.manager_data = manager_data
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def __repr__(self):
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return self.__class__.__name__ + " " + self.name + " " + self.manager_data
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class Engineer(Employee):
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def __init__(self, name, engineer_info):
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self.name = name
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self.engineer_info = engineer_info
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def __repr__(self):
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return self.__class__.__name__ + " " + self.name + " " + self.engineer_info
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pjoin = polymorphic_union({
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'manager':managers_table,
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'engineer':engineers_table
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}, 'type', 'pjoin')
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employee_mapper = mapper(Employee, pjoin, polymorphic_on=pjoin.c.type)
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manager_mapper = mapper(Manager, managers_table, inherits=employee_mapper, concrete=True, polymorphic_identity='manager')
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engineer_mapper = mapper(Engineer, engineers_table, inherits=employee_mapper, concrete=True, polymorphic_identity='engineer')
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session = create_session(bind=engine)
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m1 = Manager("pointy haired boss", "manager1")
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e1 = Engineer("wally", "engineer1")
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e2 = Engineer("dilbert", "engineer2")
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session.save(m1)
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session.save(e1)
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session.save(e2)
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session.flush()
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employees = session.query(Employee).select()
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print [e for e in employees]
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