GZ wrote:
Hi,
I have a class Record and a list key_attrs that specifies the names of
all attributes that correspond to a primary key.
I can write a function like this to get the primary key:
def get_key(instance_of_record):
return tuple(instance_of_record.__dict__[k] for k in key_attrs)
However, since key_attrs are determined at the beginning of the
program while get_key() will be called over and over again, I am
wondering if there is a way to dynamically generate a get_ley method
with the key attributes expanded to avoid the list comprehension/
generator.
For example, if key_attrs=['A','B'], I want the generated function to
be equivalent to the following:
def get_key(instance_of_record):
return (instance_of_record['A'],instance_of_record['B'] )
I realize I can use eval or exec to do this. But is there any other
way to do this?
Thanks,
gz
Hi,
you may want to do something like
class Record(object):
PRIMARY_KEY = []
def __init__(self):
for key in self.PRIMARY_KEY:
setattr(self, key, None)
def getPrimaryKeyValues(self):
return [ getattr(self, key) for key in self.PRIMARY_KEY]
class FruitRecord(Record):
PRIMARY_KEY = ['fruit_id', 'fruit_name']
JM
PS : there's a high chance that a python module already exists to access
your database with python objects.
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