constraints.sql

select c.table_schema
     , c.constraint_name
     , c.table_name
     , k.column_name
     , u.table_schema as foreign_table_schema
     , u.table_name as foreign_table_name
     , u.column_name as foreign_column_name
  from information_schema.table_constraints as c
  join information_schema.key_column_usage as k
    on c.constraint_name = k.constraint_name
   and c.table_schema = k.table_schema
  join information_schema.constraint_column_usage as u
    on u.constraint_name = c.constraint_name
   and u.table_schema = c.table_schema
 where c.constraint_type = 'FOREIGN KEY'
   and c.table_name='some_table';