On 19/07/2013 12:05pm, Victor Hooi wrote:
Hi,
Actually, while we're there - is this a suitable use of AutoField? Or is
there a better way to generate unique transactions IDs? python.uuid? Or
something better?
It depends on your use-case.
If your unique transaction number requirement is only short term, for
example delivery tracking, you can almost guarantee it doesn't matter if
you restart the numbering in future then you *could* use the id.
It only really matters if there is money and accounting involved. That
is where most of my experience has been. Hence my own "rule" to never
use a PK for transaction numbers. I have generally used a singleton
method which saves its state on receiving a close signal.
Autofield is good if you are comfortable managing restoration from
backup so your next transaction number satisfies your own business
rules. Sometimes it matters whether such numbers are really sequential.
If so and you can't tweak the next number you might have to perform
dummy transactions until the numbers satisfy you.
If you build your own generator you need something which doesn't prove
to be a bottleneck when your system scales up.
python.uuid solves such problems but may not suit your needs.
hth
Mike
Cheers,
Victor
On Friday, 19 July 2013 11:57:21 UTC+10, Victor Hooi wrote:
Hi,
Ok, thanks, I'll generate my own AutoField to track each transaction.
Just to clarify - when you say they'll be issues with migration,
what do you mean? Is it because that field is also as a FK to other
models? Or something else?
Cheers,
Victor
On Friday, 19 July 2013 11:50:25 UTC+10, Mike Dewhirst wrote:
On 19/07/2013 11:31am, Victor Hooi wrote:
> Hi,
>
> I'm just wondering - is it considered good or bad practice to
use a
> Django model's in-built ID field?
>
> Say for example you wanted a unique identifier for each
transactio -
> should you be generating your own, or can you use just
self.id <http://self.id>?
Don't go there. Generate your own. Consider what might happen if
you
needed to migrate to a different database or platform. The id
integer
will be a nightmare to manage so the unique transactions retain
their
original numbers.
Mike
>
> Cheers,
> Victor
>
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