Database objects? Persistence? Sql Server woes

Diez B. Roggisch deets at nospam.web.de
Mon Jul 30 19:35:10 CEST 2007


Mike Howarth schrieb:
> I've been having a few problems with connecting to SQL Server, initially I
> was using dblib however found some problems with returning text fields
> whereby all text fields were ignored and it bawked at multiline sql
> statements.
> 
> Having found these major stumbling blocks I've started using pymssql which
> seems less flaky. One problem I've stumbled across is that I seem to reach
> my max connections  on the database fairly easily (given how my script was
> written) and therefore have used the singleton pattern on my database
> object.
> 
> Great problem solved, or so I thought.
> 
> Using the following code I'm finding that the Set is now also being enforced
> as a singleton as well.
> 
> class Set(Database,Product):
>     
>      def __init__(self, *args, **kw): 
>          
>          Database.__init__(self)
>          Product.__init__(self)
> 
>      def dosomething(self):
>          cu = self.c.cursor()
> 
> Having sat back and thought about it, its easy to understand why this is
> occurring given I'm indicating that Set belongs to Database and therefore
> this is a singleton as well.
> 
> Being relatively new to Python I'm unsure on how to then go about using a
> database object between each class. Can anyone advise me on how they
> approach this, and whether there is a common approach to this?

You might consider using a ORM mapper, like SQLObject or SQLAlchemy. If 
they support your backend, that is.

Apart from that, this might help:

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/302088

Store a connection per thread.

Diez



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