Re: Difficulty modelling sales taxes

On 01/02/2017 06:38 AM, Melvin Davidson wrote:
>
> On Mon, Jan 2, 2017 at 6:29 AM, Frank Millman <frank(at)chagford(dot)com
> <mailto:frank(at)chagford(dot)com>> wrote:
>
>
> *From:* amul sul
> *Sent:* Monday, January 02, 2017 12:42 PM
> *To:* Frank Millman
> *Cc:* pgsql-general
> *Subject:* Re: [GENERAL] Difficulty modelling sales taxes
>
> > On Mon, Jan 2, 2017 at 4:03 PM, Frank Millman <frank(at)chagford(dot)com
> <mailto:frank(at)chagford(dot)com>> wrote:
> >
> > Hi all
> >
> >
> >
> > It is a bit ugly, because I have to use the ‘NVARCHAR code’ column from
> >
> > tax_codes, not the primary key, but I think it would work.
> >
> >
> >
> NVARCHAR ? Are you using PostgreSQL as database server?
> >
>
>
> Oops, sorry.
>
> I am testing with PostgreSQL and with SQL Server, so I was in the
> wrong mindset when I posted.
>
> I should have said VARCHAR.
>
> Frank
>
>
>
>
>
> *First, there is no need to make row_id's when you already have a valid
> primary key.

In a perfect world yes, but this is a world with ORM's as I found out
the hard way:

https://docs.djangoproject.com/en/1.10/ref/models/fields/#primary-key

"The primary key field is read-only. If you change the value of the
primary key on an existing object and then save it, a new object will be
created alongside the old one."

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com