Mike Howarth wrote:
> 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?
>
If you want to share a database object between (instances of) several
classes there are two easy ways. The absolute easiest is to create a
database connection that's global to the module. References to the
connection inside you other objects will then reference the global
database connection. e.g.:
conn = pymssql.connect(...)
class Set:
...
def dosomething(self):
self.cu = conn.cursor()
The other way is to pass the connection in to the object's __init__()
method and save it as an instance variable so it can be used inside the
instance's methods. e.g.:
conn = pymssql.connect(...)
class Set:
def __init__(self, conn, ...):
self.conn = conn
...
def dosomething(self):
self.cu = self.conn.cursor()
regards
Steve
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