Re: Records, Types, and Arrays

On Thu, May 18, 2023 at 10:06 PM Raymond Brinzer <ray(dot)brinzer(at)gmail(dot)com>
wrote:

> How do I turn arrays into composite typed values?
>

Using just SQL syntax and no string munging:

(array_val[1]::col1_type, array_val[2]::col2_type)::composite_type

> While the second point is rather far-reaching and idealistic, the first
> seems well-defined and reasonably easy.
>

> If you've taken the time to read all this, thank you. If you take the
> idea seriously, or have practical suggestions, thank you even more. If you
> correct me on something important... well, I owe much of what I know to
> people like you, so please accept my deepest gratitude.
>
> None of what you are saying is likely to ever see the light of day. If
you want to learn the SQL-way might be easier to just forget about your
idealized equivalency between composite types and array containers.

ARRAY[...] is a constructor, its output is an array container. You can
either type the elements within the constructor or leave them untyped and
put a syntactical-sugar cast on the result.

ARRAY['2023-01-01'::date,'2023-02-01'::date]
ARRAY['2023-01-01','2023-02-01']::date[]

While you've said that having all this stuff would "be quite handy" that
isn't obvious to me. It is even less obvious that any benefit would likely
be small compared to the effort to make all of this actually work.

Even if I could write: composite_type[1] instead of composite_type.column1
I don't know why I'd want to give up the expressiveness of writing the
column name.

David J.