Re: PoC: Make it possible to disallow WHERE-less UPDATE and DELETE

On 07/21/2016 06:49 AM, Tom Lane wrote:
> David Fetter <david@fetter.org> writes:
>> Please find attached a patch which makes it possible to disallow
>> UPDATEs and DELETEs which lack a WHERE clause.  As this changes query
>> behavior, I've made the new GUCs PGC_SUSET.
>
>> What say?
>

-1

> -1.  This is an express violation of the SQL standard, and at least the
> UPDATE case has reasonable use-cases.  Moreover, if your desire is to have
> training wheels for SQL, there are any number of other well-known gotchas
> that are just as dangerous, for example ye olde unintentionally-correlated
> subselect:
> https://www.postgresql.org/message-id/20160714135233.1410.92538%40wrigleys.postgresql.org
>

Yes but I used to teach a weak long class on relational databases using 
PostgreSQL. The entire week I would iterate over and over and over that 
you never use an UPDATE or DELETE without a transaction. Toward the end 
of the class we would being do problem sets that included UPDATE and 
DELETE. Guess how many would trash their data because they didn't use a 
WHERE clause AND didn't use a transaction? 50%

These weren't kids, these weren't neophytes to technology. These were 
professionals, many of them programmers (PICK).

> I wouldn't have any objection to an extension that enforces rules like
> these, but I don't think it belongs in core.

I agree it doesn't need to be in core.

JD



>
>             regards, tom lane
>
>


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