Created
April 29, 2013 12:54
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Test case for implicit merge in SQLAlchemy when PK is set in transient object
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from sqlalchemy.ext.declarative import declarative_base | |
from sqlalchemy import Column, Integer, ForeignKey, create_engine | |
from sqlalchemy.orm import sessionmaker, relationship | |
Base = declarative_base() | |
class Parent(Base): | |
__tablename__ = 'parents' | |
id = Column(Integer, primary_key=True) | |
#children = relationship('Child', cascade='all') # doesn't merge | |
children = relationship('Child', cascade='all,delete-orphan') | |
def __repr__(self): | |
return 'Parent(id=%r, children=%r)' % (self.id, self.children) | |
class Child(Base): | |
__tablename__ = 'children' | |
id = Column(Integer, primary_key=True) | |
parent_id = Column(ForeignKey(Parent.id), nullable=False) | |
parent = relationship(Parent) | |
data1 = Column(Integer, server_default='1', default=2) | |
data2 = Column(Integer, server_default='1', default=2) | |
def __repr__(self): | |
return 'Child(id=%r, data1=%r, data2=%r)' % ( | |
self.id, self.data1, self.data2) | |
engine = create_engine('sqlite://', echo=True) | |
Base.metadata.create_all(engine) | |
db = sessionmaker(bind=engine)() | |
p = Parent(children=[Child(data1=3, data2=3)]) | |
db.add(p) | |
db.commit() | |
print p | |
p_id = p.id | |
c_id = p.children[0].id | |
db.expunge_all() | |
p = db.query(Parent).get(p_id) | |
#print p # Access to children might affect behavior | |
p.children = [Child(id=c_id, data1=None)] | |
db.commit() | |
db.expunge_all() | |
p = db.query(Parent).get(p_id) | |
print p |
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