Обсуждение: Create recursive view schema.name

Hi all,

I'm using PG 9.6, learning the "recursive" queries.

I have a working recursive-CTE query, and I tried wrapping it in a view:
reading the documentation I found the "CREATE RECURSIVE VIEW" form, so I tried
it.

It works as far as I use a "simple" name for the view:

  CREATE OR REPLACE RECURSIVE VIEW procedure_sites (procedure_id, site_id) AS
    SELECT pr.id, pr.site_id
    FROM sop.procedures pr
      JOIN sop.phases ph on ph.procedure_id = pr.id

    UNION ALL

    SELECT s.procedure_id, ss.site_id
    FROM procedure_sites s
      JOIN risk.company_sites ss ON ss.id = s.site_id
    WHERE ss.site_id IS NOT NULL;

but I get an error when I create it in a specific schema:

  CREATE OR REPLACE RECURSIVE VIEW sop.procedure_sites (procedure_id, site_id) AS
    SELECT pr.id, pr.site_id
    FROM sop.procedures pr
      JOIN sop.phases ph on ph.procedure_id = pr.id

    UNION ALL

    SELECT s.procedure_id, ss.site_id
    FROM sop.procedure_sites s
      JOIN risk.company_sites ss ON ss.id = s.site_id
    WHERE ss.site_id IS NOT NULL;

  ERROR:  relation "sop.procedure_sites" does not exist
  RIGA 8:     JOIN sop.procedure_sites s ON s.site_id = ss.id
                   ^

Am I missing something?

Thanks in advance for any hint,
ciao, lele.
--
nickname: Lele Gaifax | Quando vivrò di quello che ho pensato ieri
real: Emanuele Gaifas | comincerò ad aver paura di chi mi copia.
lele@metapensiero.it  |                 -- Fortunato Depero, 1929.

Lele Gaifax <lele@metapensiero.it> writes:
> I have a working recursive-CTE query, and I tried wrapping it in a view:
> reading the documentation I found the "CREATE RECURSIVE VIEW" form, so I tried
> it.

> It works as far as I use a "simple" name for the view:
> but I get an error when I create it in a specific schema:

The manual says
    CREATE RECURSIVE VIEW name (columns) AS SELECT ...;
    is equivalent to
    CREATE VIEW name AS WITH RECURSIVE name (columns) AS (SELECT ...) SELECT columns FROM name;

I guess it could be more explicit about the fact that the implied CTE just
has the base name of the view; but since CTE names can't be qualified,
that's not that hard to guess.  Short answer is that you don't qualify the
view's internal self-reference, even if you are using a schema name in the
CREATE.

            regards, tom lane

Tom Lane <tgl@sss.pgh.pa.us> writes:

> The manual says
>     CREATE RECURSIVE VIEW name (columns) AS SELECT ...;
>     is equivalent to
>     CREATE VIEW name AS WITH RECURSIVE name (columns) AS (SELECT ...) SELECT columns FROM name;
>
> I guess it could be more explicit about the fact that the implied CTE just
> has the base name of the view; but since CTE names can't be qualified,
> that's not that hard to guess.  Short answer is that you don't qualify the
> view's internal self-reference, even if you are using a schema name in the
> CREATE.

Thank you Tom, it works.

I agree with you that the doc could/should be fixed/enhanced, because the
explanation of "name" is immediately following the snippet you cited, and it
says "The name (optionally schema-qualified) of a view to be created": it
would never occurred to me that I could use a not-qualified name within the
view.

bye, lele.
--
nickname: Lele Gaifax | Quando vivrò di quello che ho pensato ieri
real: Emanuele Gaifas | comincerò ad aver paura di chi mi copia.
lele@metapensiero.it  |                 -- Fortunato Depero, 1929.