Re: INSERT ... ON CONFLICT DO UPDATE with _any_ constraint

On 19 May 2015 at 17:10, Peter Geoghegan <pg(at)heroku(dot)com> wrote:

> On Tue, May 19, 2015 at 1:57 PM, Simon Riggs <simon(at)2ndquadrant(dot)com>
> wrote:
> > We should allow DO UPDATE to exclude a constraint and apply a
> deterministic
> > order to the constraints. 1. PK if it exists. 2. Replica Identity, when
> not
> > PK, 3. UNIQUE constraints in name order, like triggers, so users can
> define
> > a default evaluation order, just like they do with triggers.
>
> That seems like something way worse than just allowing it for all
> constraints.
>

I'm talking about the evaluation order; it would still match all
constraints, otherwise they wouldn't be constraints.

> 2) Compatibility with MySQL
>
> But what you describe isn't compatible with MySQL. It's totally novel.
>

Upthread you said

"It's trivial to modify Postgres to not require that a specific unique
index be inferred, so that you can omit the inference specification
for DO UPDATE just as you can for DO NOTHING. That would make it work
in a similar way to MySQL"

Similar is good and useful. Full compatibility is even better.

--
Simon Riggs http://www.2ndQuadrant.com/
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