Achim Domma (ProCoders) wrote:
> Hi,
>
> I've seen Brad Bollenbach very good talk at Europython, and now I finaly
> found the time to give SQLObject a try. I really like it, but have some
> questions:
>
> - In the examples, the connection is always hardcoded in the module, where
> my classes are definied. In real world apps I would like to specifiy the
> connection from outside of the module. I might have two different instances
> of my app, using two different servers/databases. How would I do that?
>
> - What's about aggregate columns? I want to build a system with some kind of
> ranking mechanism, where I usually only want to show the average ranking. As
> far as I understand, I would have to calculate that value 'by hand', if I
> use SQLObject. Is that right?
>
> regards,
> Achim
>
I'll leave others to answer your question on aggregate columns, but for
connections I do the same thing that I would for 'raw' db-api code.
I store the user name, password, host name and database name in a
configuration file and then read that in at the top of my module. The
values are placed in a dictionary (actually, they are stored in dict
format but that's just because I'm lazy) and then used as arguments to
the connection attribute. e.g.;
"""
import os.path
CONFIG_FILENAME='myconfig.txt'
if '__file__' in locals():
CONFIG=os.path.dirname(__file__)+'/'+CONFIG_FILENAME
else:
CONFIG=CONFIG_FILENAME
config=readAndEvalFile(CONFIG)
__connection__=MySQLConnection(db=config['db'], host=config['host'],
user=config['user'], passwd=config['passwd'])
"""
The only magic there is the readAndEvalFile function which simply reads
the file you supply and turns it into a dictionary.
Of course, you don't need to store the values in a configuration file.
If you are building a web or gui front end to your application you can
prompt for the values and then pass them in to your module at run time.
Regards,
Andy
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