select target_schema as table_schema, target_table as table_name, a.attname as column_name, 
conname AS constraint_name, 
CASE WHEN contype='f' THEN 'FOREIGN KEY'
WHEN contype='p' THEN 'PRIMARY KEY' 
WHEN contype='u' THEN 'UNIQUE'
WHEN contype='t' THEN 'CONSTRAINT TRIGGER'
WHEN contype='c' THEN 'CHECK'
ELSE 'EXCLUSION' END AS constraint_type,
condeferrable AS is_deferrable,
condeferred AS is_deferred
from (select 
(select nspname from pg_namespace where oid=m.relnamespace) as target_schema,
m.relname as target_table, 
m.oid as target_table_oid,
conname,
contype,
condeferrable,
condeferred,
unnest(o.conkey) AS target_col
from pg_constraint o inner join pg_class c on c.oid = o.conrelid
inner join pg_class m on m.oid = o.conrelid
where o.conrelid in (select oid from pg_class c where c.relkind = 'r')
and (condeferrable=true or condeferred=true)) t
inner join pg_attribute a on t.target_col = a.attnum and t.target_table_oid = a.attrelid and a.attisdropped = false
order by target_schema, target_table, attname;