Re: A Modest Upgrade Proposal

On 7/17/16 2:22 PM, Petr Jelinek wrote:
>> I generally agree, but I think the more important question is "Why?". Is
>> it becouse DDL looks more like a sentence? Is it because arrays are a
>> PITA? Is it too hard to call functions?
>
> For me it's many small reasons. I want to store it in catalogs and some
> things there are nicer when you manipulate using standard DDL processing
> (like dependencies for example).

Fair point.

> The syntax is also bit nicer. Our
> documentation works better for DDLs than functions (that's something we
> should fix but I am not doing it as part of this patch). Same goes for
> psql tab completion. We automatically gain things like event triggers.

I'd think all of those we'd want to be able to support for functions as
well...

> The support in pg_dump is also more straightforward with DDL.

Hmm... not sure why that is. It does seem to me that support for
extension configuration isn't as strong as it could be.

> It might make sense to have functions for manipulating slots and origins
> as those are just primitives which user should not have to fiddle with
> but for things that are directly meant for user interaction DDL just
> feels better.

I do agree that DDL "feels better" (which I think is what JD was
alluding too).

I had a secret agenda in asking why it's better though: can we find a
way to allow extensions to do "DDL-ish" things in a better way than how
they're stuck doing them today. I suspect it will never be practical to
have extensions modifying grammar willy-nilly, but maybe there's some
other things we could do to make life easier. One thought is an
"extension command" mode you can enter that means everything you're
typing gets treated as a call to a function in that extension:

EXTENSION MODE citus;
master_create_distributed_table 'github_events', 'created_at', 'append';
EXTENSION MODE;

instead of SELECT master_create_distributed_table('github_events',
'created_at', 'append');

obviously that's completely pointless for a single command, but if you
needed to do a bunch of things it starts saving typing.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
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