Hi all,
I just started using SQLA, and I am confused by some cascade delete
behaviour I am seeing. Please see the code and tests below which show that
the session is seeing table rows in one area and not in the other:
CODE:
print Product1Mod3
__tablename__ = 'products'
id = Column(Integer, primary_key=True)
product_name = Column(String(250), unique=True)
vendor_id = Column(Integer, ForeignKey('vendors.id'), nullable=False)
vendor = relationship('Vendor', backref = backref('products',
order_by=id, cascade="all, delete-orphan"))
def __init__(self, product_name, vendor_id):
self.product_name = product_name
self.vendor_id = vendor_id
def __repr__(self):
return '<Product: %r Product ID: %r Vendor ID: %r>' %
(self.product_name, self.id, self.vendor_id)
class Module(Base):
__tablename__ = 'modules'
id = Column(Integer, primary_key=True)
module_name = Column(String(250), unique=True)
product_id = Column(Integer, ForeignKey('products.id'), nullable=False)
product = relationship('Product', backref = backref('modules',
order_by=id, cascade="all, delete-orphan"))
def __init__(self, module_name, product_id):
self.module_name = module_name
self.product_id = product_id
def __repr__(self):
return '<Module: %r Module ID: %r Product ID: %r>' %
(self.module_name, self.id ,self.product_id)
TESTING:
msg('Module Tests')
Product2Mod1 = Module('Product2Mod1',1)
Product2Mod2 = Module('Product2Mod2',1)
Product1Mod1 = Module('Product1Mod1',2)
Product1Mod2 = Module('Product1Mod2',2)
Product1Mod3 = Module('Product1Mod3',2)
db_session.add(Product2Mod1)
db_session.add(Product2Mod2)
db_session.add(Product1Mod1)
db_session.add(Product1Mod2)
db_session.add(Product1Mod3)
db_session.commit()
msg("Product2Mod1 Product:")
print Product2Mod1.product
msg('delete tests')
print "Query to show all products: \n"
print Product.query.all()
print "\nQuery to show all modules: \n"
print Module.query.all()
print "\ndeleting product 1: db_session.delete(Product1) -->
db_session.commit()"
db_session.delete(Product1)
db_session.commit()
print "\nQuery to check for changes with products and modules, shows that
the modules and product are gone:\n"
print Product.query.all()
print Module.query.all()
print "\nThe modules below belong to the deleted product, they should have
disappeared, but do not: <-- NOT SURE WHY THIS IS HAPPENING"
print Product1Mod1
print Product1Mod2
print Product1Mod3
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