test=# create table test01(
test(# id int primary key,
test(# col1 varchar(20)
test(# );
CREATE TABLE
 
test=# create table test02(
test(# id int primary key,
test(# test01_id int references test01(id),
test(# col1 varchar(20)
test(# );
CREATE TABLE

test=# insert into test01 values (1, 'a');
INSERT 0 1
test=# insert into test01 values (2, 'b');
INSERT 0 1
test=# insert into test01 values (3, 'c');
INSERT 0 1
test=# insert into test02 values (1, 1, 'a');
INSERT 0 1
test=# insert into test02 values (2, 1, 'a');
INSERT 0 1
test=# insert into test02 values (3, 1, 'a');
INSERT 0 1
test=# insert into test02 values (4, 2, 'b');
INSERT 0 1
test=# insert into test02 values (5, 2, 'b');
INSERT 0 1
test=# insert into test02 values (6, 11, 'b');
ERROR: insert or update on table "test02" violates foreign key constraint "test02_test01_id_fkey"
DETAIL: Key (test01_id)=(11) is not present in table "test01".

test=# SELECT
tc.constraint_name,
tc.table_name, # 子表
kcu.column_name,
ccu.table_name AS foreign_table_name, # 主表
ccu.column_name AS foreign_column_name,
tc.is_deferrable,
tc.initially_deferred
FROM
information_schema.table_constraints AS tc
JOIN information_schema.key_column_usage AS kcu ON tc.constraint_name = kcu.constraint_name
JOIN information_schema.constraint_column_usage AS ccu ON ccu.constraint_name = tc.constraint_name
where constraint_type = 'FOREIGN KEY' AND ccu.table_name='test01'; # 输入主表
constraint_name | table_name | column_name | foreign_table_name | foreign_column_name | is_deferrable | initially_deferred
-----------------------+------------+-------------+--------------------+---------------------+---------------+--------------------
test02_test01_id_fkey | test02 | test01_id | test01 | id | NO | NO
(1 row)

test=# SELECT
tc.constraint_name,
tc.table_name, # 子表
kcu.column_name,
ccu.table_name AS foreign_table_name,
ccu.column_name AS foreign_column_name, # 主表
tc.is_deferrable,
tc.initially_deferred
FROM
information_schema.table_constraints AS tc
JOIN information_schema.key_column_usage AS kcu ON tc.constraint_name = kcu.constraint_name
JOIN information_schema.constraint_column_usage AS ccu ON ccu.constraint_name = tc.constraint_name
WHERE constraint_type = 'FOREIGN KEY' AND tc.table_name='test02'; # 输入子表
constraint_name | table_name | column_name | foreign_table_name | foreign_column_name | is_deferrable | initially_deferred
-----------------------+------------+-------------+--------------------+---------------------+---------------+--------------------
test02_test01_id_fkey | test02 | test01_id | test01 | id | NO | NO
(1 row)

SELECT x.table_name,
    x.column_name
 FROM information_schema.key_column_usage x
 INNER JOIN (SELECT t.relname, 
            a.conname 
         FROM pg_constraint a 
         INNER JOIN pg_class ft
             ON ft.oid = a.confrelid 
         INNER JOIN pg_class t 
             ON t.oid = a.conrelid
        WHERE a.contype = 'f' 
         AND a.confrelid =
            (select e.oid 
             from pg_class e
             where e.relname = 'xxx_table')
        ) tp 
     ON (x.table_name = tp.relname AND
       x.constraint_name = tp.conname)