相互依存関係のあるSQLスクリプトの実行

他に依存しないすべてのビューで開始し、これらに依存するビューを再帰的に追加する単純な再帰クエリを作成できます。次に、これらのビューのビュー定義を正しい順序で出力すると、スクリプトが作成されます。

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);