Having overcome my first hurdle with the factory pattern, I've now hit
another stumbling block
At the moment I'm trying to return around 2000 records from a db and load up
the relevant product object, what I've found is this is running extremely
slowly (> 20mins), the db is normalized and indexes exist.
Can anyone advise on how best I could speed this up?
def getWebRangeProducts(self):
if self.c.connected:
cu = self.c.cursor #create the cursor
sql = "SELECT type, code FROM products"
cu.execute(sql)
if cu.rowcount > 0:
rows = cu.fetchall()
for row in rows:
self.loadProduct(row[0].strip(),row[1].strip())
return self.products
def loadProduct(self,type,product_code):
print type + ":" + product_code
if type == 'I':
try:
product = factory('Item', product_code)
self.products.append(product)
except:
print 'problem occured:' + type + ':' + product_code
elif type == 'S':
try:
item_set = factory('Set', product_code)
item_set.getItems()
self.products.extend(item_set.getItems())
except:
print 'problem occured:' + type + ':' + product_code
else:
pass
Bruno Desthuilliers-5 wrote:
>
> Mike Howarth a écrit :
>> Hi
>>
>> I was wondering whether anyone could help me, I'm pretty new to python
>> coming from a PHP background and I'm having a few products in getting my
>> head round how to write the factory pattern within python.
>>
>> I'm currently looking to try to return values from a db and load up the
>> relevant objects, values returned are product type (I,S) and product code
>> (123).
>>
>> At the moment I've adapted some code I've found illustrating the factory
>> method but ideally I would like to use the type to load up the relevant
>> object.
>>
>> Another issue I've found is that I don't seem to be able to access to the
>> price attribute of each of the object. I'm sure these are very
>> straightforward issues however I seem to have tied myself in knots over
>> this
>> and could do with a fresh set of 'pythonic' eyes to help me out.
>>
>> registry = {}
>>
>> class MetaBase(type):
>> def __init__(cls, name, bases, dict):
>> registry[name] = cls
>>
>> class Product(object):
>> __metaclass__ = MetaBase
>>
>> class Item(Product):
>> def __init__(self, *args, **kw):
>> self.price = 1
>>
>> class Set(Product):
>> def __init__(self, *args, **kw):
>> self.price = 2
>>
>> def factory(kind, *args, **kw):
>> return registry[kind](*args, **kw)
>>
>>
>> item = registry['Item']
>
> This returns the Item *class*, not an instance of... So the following:
>
>> print item.price
>
> cannot work, since price is an instance attribute, not a class attribute.
>
> What you want is:
>
> item = factory('Item')
> print item.price
>
> HTH
> --
> http://mail.python.org/mailman/listinfo/python-list
>
>
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