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from sqlalchemy import *
from timeit import Timer
import sys
meta = DynamicMetaData("time_trial")
orders = Table('orders', meta,
Column('id', Integer, Sequence('order_id_seq'), primary_key = True),
)
items = Table('items', meta,
Column('id', Integer, Sequence('item_id_seq'), primary_key = True),
Column('order_id', Integer, ForeignKey(orders.c.id), nullable=False),
)
attributes = Table('attributes', meta,
Column('id', Integer, Sequence('attribute_id_seq'), primary_key = True),
Column('item_id', Integer, ForeignKey(items.c.id), nullable=False),
)
values = Table('values', meta,
Column('id', Integer, Sequence('value_id_seq'), primary_key = True),
Column('attribute_id', Integer, ForeignKey(attributes.c.id), nullable=False),
)
class Order(object): pass
class Item(object): pass
class Attribute(object): pass
class Value(object): pass
valueMapper = mapper(Value, values)
attrMapper = mapper(Attribute, attributes, properties=dict(
values=relation(valueMapper, cascade="save-update", backref="attribute")
))
itemMapper = mapper(Item, items, properties=dict(
attributes=relation(attrMapper, cascade="save-update", backref="item")
))
orderMapper = mapper(Order, orders, properties=dict(
items=relation(itemMapper, cascade="save-update", backref="order")
))
class TimeTrial(object):
def create_fwd_assoc(self):
item = Item()
self.order.items.append(item)
for attrid in range(10):
attr = Attribute()
item.attributes.append(attr)
for valueid in range(5):
val = Value()
attr.values.append(val)
def create_back_assoc(self):
item = Item()
item.order = self.order
for attrid in range(10):
attr = Attribute()
attr.item = item
for valueid in range(5):
val = Value()
val.attribute = attr
def run(self, number):
s = create_session()
self.order = order = Order()
s.save(order)
ctime = 0.0
timer = Timer("create_it()", "from __main__ import create_it")
for n in xrange(number):
t = timer.timeit(1)
print "Time to create item %i: %.5f sec" % (n, t)
ctime += t
assert len(order.items) == 10
assert sum(len(item.attributes) for item in order.items) == 100
assert sum(len(attr.values) for item in order.items for attr in item.attributes) == 500
assert len(s.new) == 611
print "Created 610 objects in %.5f sec" % ctime
if __name__ == "__main__":
tt = TimeTrial()
print "\nCreate forward associations"
create_it = tt.create_fwd_assoc
tt.run(10)
print "\nCreate backward associations"
create_it = tt.create_back_assoc
tt.run(10)
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