Puoi scrivere una semplice query ricorsiva che inizia con tutte le viste che non dipendono da altre e aggiunge ricorsivamente le viste che dipendono da queste. Quindi emetti la definizione della vista per queste viste nell'ordine corretto e hai il tuo script:
WITH RECURSIVE viewids AS (
/* all views that don't depend on other views */
SELECT t.oid, 1 as level
FROM pg_class t
JOIN pg_rewrite AS r ON r.ev_class = t.oid
WHERE r.rulename = '_RETURN'
AND t.relkind = 'v'
AND t.relnamespace NOT IN ('pg_catalog'::regnamespace,
'information_schema'::regnamespace,
'pg_toast'::regnamespace)
AND NOT EXISTS (
/* depends on a view */
SELECT 1
FROM pg_depend AS d
JOIN pg_class AS t2 ON d.refobjid = t2.oid
WHERE d.objid = r.oid
AND d.classid = 'pg_rewrite'::regclass
AND d.refclassid = 'pg_class'::regclass
AND d.deptype = 'n'
AND d.refobjsubid <> 0
AND t2.relkind = 'v'
)
AND NOT EXISTS (
/* depends on an extension */
SELECT 1
FROM pg_depend
WHERE objid = t.oid
AND classid = 'pg_class'::regclass
AND refclassid = 'pg_extension'::regclass
AND deptype = 'e'
)
UNION ALL
/* all views that depend on these views */
SELECT t.oid, viewids.level + 1
FROM pg_class AS t
JOIN pg_rewrite AS r ON r.ev_class = t.oid
JOIN pg_depend AS d ON d.objid = r.oid
JOIN viewids ON viewids.oid = d.refobjid
WHERE t.relkind = 'v'
AND r.rulename = '_RETURN'
AND d.classid = 'pg_rewrite'::regclass
AND d.refclassid = 'pg_class'::regclass
AND d.deptype = 'n'
AND d.refobjsubid <> 0
)
/* order the views by level, eliminating duplicates */
SELECT format('CREATE VIEW %s AS%s',
oid::regclass,
pg_get_viewdef(oid::regclass))
FROM viewids
GROUP BY oid
ORDER BY max(level);
