Re: Enforce primary key on every table during dev?

On 03/01/2018 12:32 PM, Daevor The Devoted wrote:
>
>
> On Thu, Mar 1, 2018 at 8:18 PM, Ron Johnson <ron(dot)l(dot)johnson(at)cox(dot)net
> <mailto:ron(dot)l(dot)johnson(at)cox(dot)net>> wrote:
>
>
> On 03/01/2018 11:47 AM, Daevor The Devoted wrote:
>>
>> On Thu, Mar 1, 2018 at 2:07 PM, Rakesh Kumar <rakeshkumar464(at)aol(dot)com
>> <mailto:rakeshkumar464(at)aol(dot)com>> wrote:
>>
>>
>> >Adding a surrogate key to such a table just adds overhead,
>> although that could be useful
>> >in case specific rows need updating or deleting without also
>> modifying the other rows with
>> >that same data - normally, only insertions and selections happen
>> on such tables though,
>> >and updates or deletes are absolutely forbidden - corrections
>> happen by inserting rows with
>> >an opposite transaction.
>>
>> I routinely add surrogate keys like serial col to a table already
>> having a nice candidate keys
>> to make it easy to join tables.  SQL starts looking ungainly when
>> you have a 3 col primary
>> key and need to join it with child tables.
>>
>>
>> I was always of the opinion that a mandatory surrogate key (as you
>> describe) is good practice.
>> Sure there may be a unique key according to business logic (which may
>> be consist of those "ungainly" multiple columns), but guess what,
>> business logic changes, and then you're screwed!
>
> And so you drop the existing index and build a new one. I've done it
> before, and I'll do it again.
>
>> So using a primary key whose sole purpose is to be a primary key
>> makes perfect sense to me.
>
> I can't stand synthetic keys.  By their very nature, they're so
> purposelessly arbitrary, and allow you to insert garbage into the table.
>
>
> Could you perhaps elaborate on how a surrogate key allows one to insert
> garbage into the table? I'm afraid I don't quite get what you're saying.

If your only unique index is a synthetic key, then you can insert the same
"business data" multiple times with different synthetic keys.

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