Re: Wiki editor request: Fixing Sequences
| От | Joe Krill |
|---|---|
| Тема | Re: Wiki editor request: Fixing Sequences |
| Дата | |
| Msg-id | CAGjD_Eb8SpD0v6sOQvOdRpzUfZP_u8q4bcL18XQzWG65pBzqkw@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Wiki editor request: Fixing Sequences (Alvaro Herrera <alvherre@2ndquadrant.com>) |
| Список | pgsql-www |
Thanks Álvaro! I hadn't considered that the sequence could be in a different schema. I was only using the `quote_foo` functions because the existing query uses it, but using format definitely makes it much easier to read. I'm not totally clear on what needs to be cast to a regclass, though. Would you mind elaborating on that? All of the oid comparisons are to other oid types, so I didn't think there was a need to cast. But this is getting a bit outside of my scope of knowledge on this stuff.
Here's the updated query using format and the correct schema:
SELECT
format('SELECT SETVAL(''%I.%I'', COALESCE(MAX(%I), 1) ) FROM %I.%I;', SEQUENCE_SCHEMAS.nspname, SEQUENCES.relname, COLUMNS.attname, TABLE_SCHEMAS.nspname, TABLES.relname)
FROM pg_class SEQUENCES
INNER JOIN pg_namespace SEQUENCE_SCHEMAS ON SEQUENCE_SCHEMAS.oid = SEQUENCES.relnamespace
INNER JOIN pg_depend ON pg_depend.objid = SEQUENCES.oid
INNER JOIN pg_attribute COLUMNS ON COLUMNS.attrelid = pg_depend.refobjid
AND COLUMNS.attnum = pg_depend.refobjsubid
INNER JOIN pg_class TABLES ON TABLES.oid = COLUMNS.attrelid
INNER JOIN pg_namespace TABLE_SCHEMAS ON TABLE_SCHEMAS.oid = TABLES.relnamespace
WHERE SEQUENCES.relkind = 'S';
Thanks,
Joe
On Tue, Mar 27, 2018 at 8:16 PM Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
Joe Krill wrote:
> Hello,
>
> My wiki account name is JoeK
>
> I was hoping to share an updated Fixing Sequences query (
> https://wiki.postgresql.org/wiki/Fixing_Sequences). We tried to use the
> query as it currently stands and ran into a handful of problems.
You're an editor now. I think your proposed query will fail if you have
a default sequence in a different schema than the table it's default
for; watch out for that case. Also, I propose that instead of || and
quote_foo(), the function "format" and cast of the pg_class.oid column to
regclass result in easier-to-read code.
Thanks
> SELECT 'SELECT SETVAL(' ||
> quote_literal(quote_ident(SCHEMAS.nspname) || '.' ||
> quote_ident(SEQUENCES.relname)) ||
> ', COALESCE(MAX(' ||quote_ident(COLUMNS.attname)|| '), 1) ) FROM ' ||
> quote_ident(SCHEMAS.nspname)|| '.'||quote_ident(TABLES.relname)|| ';'
> FROM pg_class SEQUENCES
> INNER JOIN pg_namespace SCHEMAS ON SCHEMAS.oid = SEQUENCES.relnamespace
> INNER JOIN pg_depend ON pg_depend.objid = SEQUENCES.oid
> INNER JOIN pg_attribute COLUMNS ON COLUMNS.attrelid = pg_depend.refobjid
> AND COLUMNS.attnum = pg_depend.refobjsubid
> INNER JOIN pg_class TABLES ON TABLES.oid = COLUMNS.attrelid
> WHERE SEQUENCES.relkind = 'S'
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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