From: | Matthew Woodcraft <matthew(at)woodcraft(dot)me(dot)uk> |
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To: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: UPSERT wiki page, and SQL MERGE syntax |
Date: | 2014-10-12 12:36:51 |
Message-ID: | m1dsl4$k6o$1@ger.gmane.org |
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Thread: | |
Lists: | pgsql-hackers |
On 2014-10-10 19:44, Kevin Grittner wrote:
> Peter Geoghegan <pg(at)heroku(dot)com> wrote:
>> People keep remarking that they don't like that you can (optionally)
>> name a unique index explicitly,
[...]
> To restate: to do so is conflating the logical definition of the
> database with a particular implementation detail. As just one
> reason that is a bad idea: we can look up unique indexes on the
> specified columns, but if we implement a other storage techniques
> where there is no such thing as a unique index on the columns, yet
> manage to duplicate the semantics (yes, stranger things have
> happened), people can't migrate to the new structure without
> rewriting their queries
Wouldn't it be good enough to define the 'WITHIN' as expecting a
unique-constraint name rather than an index name (even though those
happen to be the same strings)?
I think constraints are part of the logical definition of the database,
and a new storage technique which doesn't use indexes should still have
names for its unique constraints.
-M-
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