Cycles in relationships

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WITH RECURSIVE fk AS (SELECT
o.conname,
(SELECT nspname FROM pg_namespace WHERE oid=f.relnamespace) AS foreign_schema,
f.relname AS foreign_table,
(SELECT nspname FROM pg_namespace WHERE oid=c.relnamespace) AS target_schema,
c.relname AS target_table
FROM pg_constraint o inner join pg_class c on c.oid = o.conrelid
inner join pg_class f on f.oid = o.confrelid
WHERE o.contype = 'f'),
fk_input AS (SELECT target_schema, target_table, foreign_schema, foreign_table 
FROM fk
WHERE foreign_schema || '.' || foreign_table <> target_schema || '.' || target_table
UNION SELECT table_schema, table_name, NULL AS foreign_schema, NULL AS foreign_table
FROM INFORMATION_SCHEMA.tables AS t
WHERE t.table_schema NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL)
AND table_type='BASE TABLE'
AND NOT EXISTS (SELECT * 
FROM fk
WHERE t.table_schema=fk.target_schema
AND t.table_name=fk.target_table)),
fk_hierarchy AS (SELECT target_schema, target_table, foreign_schema, foreign_table, 1 AS level 
FROM fk_input 
WHERE foreign_schema IS NULL
AND foreign_table IS NULL
UNION ALL 
SELECT f.target_schema, f.target_table, f.foreign_schema, f.foreign_table, fh.level+1 AS level 
FROM fk_input AS f INNER JOIN fk_hierarchy AS fh ON f.foreign_schema=fh.target_schema AND f.foreign_table=fh.target_table)
CYCLE target_schema,  target_table SET is_cycle USING path
SELECT target_schema, target_table, foreign_schema, foreign_table, level, is_cycle, path 
FROM fk_hierarchy 
WHERE EXISTS (SELECT *
FROM fk_hierarchy
WHERE is_cycle='t')
ORDER BY is_cycle DESC, level, target_schema, target_table;