40 lines
904 B
Python
40 lines
904 B
Python
from sqlalchemy import create_engine
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from sqlalchemy import Column, Integer, String
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from sqlalchemy.orm import sessionmaker
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from sqlalchemy.ext.declarative import declarative_base
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engine = create_engine('sqlite:///:memory:', echo=True)
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Session = sessionmaker(bind=engine)
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Base = declarative_base()
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class Toaster(Base):
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__tablename__ = 'toasters'
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id = Column(Integer, primary_key=True)
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name = Column(String)
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color = Column(String)
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def toaster_exists_bad(toaster_id):
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session = Session()
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return bool(session.query(Toaster).filter_by(id=toaster_id).first())
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def toaster_exists_good(toaster_id):
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session = Session()
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query = session.query(Toaster).filter_by(id=toaster_id)
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return session.query(query.exists()).scalar()
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def main():
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Base.metadata.create_all(engine)
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toaster_exists_bad(1)
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toaster_exists_good(2)
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if __name__ == "__main__":
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main()
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