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.l.johnson@cox.net 
> <mailto:ron.l.johnson@cox.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@aol.com
>>     <mailto:rakeshkumar464@aol.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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