Re: CREATE SCHEMA ... CREATE DOMAIN support

On Sun, 1 Dec 2024 at 04:33, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I looked at several iterations of the SQL standard
> and cannot find any support for the idea that CREATE SCHEMA needs to
> be any smarter than that.  I'd also argue that doing anything else is
> a POLA violation.  It's especially a POLA violation if the code
> rearranges a valid user-written command order into an invalid order,
> which is inevitable if we stick with the current approach.

Agreed.

> So attached is a draft patch that simplifies the rule to "do the
> subcommands in the order written".

+1 on this idea.

Here is my 2c to this draft:
1) Report error position on newly added check for temp relation in
non-temp schema.

> +                 errmsg("cannot create temporary relation in non-temporary schema"),
> +                 parser_errposition(pstate, relation->location)));

2)
I added some regression tests that might be worth adding:
a) check for a temporary table created within a non-temporary schema
in create_table.sql, akin to existing check in create_view.sql.
b) Also explicitly check that old-style sql creation does not work.
That is, for example,
CREATE SCHEMA test_ns_schema_3
       CREATE VIEW abcd_view AS
              SELECT a FROM abcd
       CREATE TABLE abcd (
              a serial
       );

fails.

3) Why do we delete this in `create_schema.sgml`? Is this untrue? It
is about order of definition, not creation, isn't it?

> -   The SQL standard specifies that the subcommands in <command>CREATE
> -   SCHEMA</command> can appear in any order.


P.S.
This section in SQL-92 is the only information I could find about
order of creation.

```
         3) Those objects defined by <schema element>s (base tables, views,
            constraints, domains, assertions, character sets, translations,
            collations, privileges) and their associated descriptors are
            effectively created.
```
Look like we are 100% to do it in order of definition


-- 
Best regards,
Kirill Reshke