On Mon, Jan 2, 2017 at 9:58 AM, Adrian Klaver <adrian.kla...@aklaver.com> wrote:
> On 01/02/2017 06:38 AM, Melvin Davidson wrote: > >> >> On Mon, Jan 2, 2017 at 6:29 AM, Frank Millman <fr...@chagford.com >> <mailto:fr...@chagford.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 <fr...@chagford.com >> <mailto:fr...@chagford.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.kla...@aklaver.com > *>https://docs.djangoproject.com/en/1.10/ref/models/fields/#primary-key <https://docs.djangoproject.com/en/1.10/ref/models/fields/#primary-key>* *You are quoting from a django document. Please don't muddle the waters.So you are saying this will not work?UPDATE mytable SET mykey = 'new_value' WHERE mykey = 'old_value';DELETE FROM mytable WHERE mykey = 'old_value';* *Happy New Year Adrian* -- *Melvin Davidson* I reserve the right to fantasize. Whether or not you wish to share my fantasy is entirely up to you.
