WITH surrogate_key AS (SELECT A.table_schema, A.table_name, B.column_name 
FROM information_schema.table_constraints A
JOIN information_schema.constraint_column_usage B
ON A.table_schema = B.table_schema
AND A.table_name = B.table_name
AND A.constraint_name = B.constraint_name
AND A.constraint_type IN ('PRIMARY KEY', 'UNIQUE')
INNER JOIN information_schema.columns C
ON B.table_schema=C.table_schema
AND B.table_name = C.table_name
AND B.column_name=C.column_name
INNER JOIN information_schema.schemata S
ON A.table_schema=S.schema_name
WHERE  (C.column_default LIKE '%nextval%' OR C.is_identity='YES') AND
(A.table_schema = 'public'
OR S.schema_owner<>'postgres') ),
fk as (select 
o.conname,
(select nspname from pg_namespace where oid=f.relnamespace) as foreign_schema,
f.relname as foreign_table,
f.oid as foreign_table_oid,
unnest(o.confkey) AS foreign_col,
(select nspname from pg_namespace where oid=c.relnamespace) as target_schema,
c.relname as target_table, 
c.oid as target_table_oid,
unnest(o.conkey) AS target_col
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.confmatchtype<>'f' and o.contype = 'f' and o.confupdtype='c'),
fk_columns as (
select fk.conname, fk.foreign_schema, fk.foreign_table, a_foreign.attname as foreign_col, fk.target_schema, fk.target_table, a_target.attname as target_col
from fk inner join pg_attribute a_foreign on fk.foreign_col = a_foreign.attnum and fk.foreign_table_oid = a_foreign.attrelid and a_foreign.attisdropped = false
inner join pg_attribute a_target on fk.target_col = a_target.attnum and fk.target_table_oid = a_target.attrelid and a_target.attisdropped = false)
SELECT format('ALTER TABLE %1$I.%2$I DROP CONSTRAINT %3$I;', target_schema, target_table, conname) AS statements
FROM fk_columns
WHERE (foreign_schema, foreign_table, foreign_col) IN (SELECT table_schema, table_name, column_name FROM surrogate_key)
ORDER BY target_schema, target_table, target_col;