How to do it…

You can use the following command from psql to display full information about a table the constraints that are defined upon it, and the constraints that reference it:

\d+ orders

You can also get specific details of the constraints by using the following query:

SELECT * FROM pg_constraint
WHERE confrelid = 'orders'::regclass;

Unfortunately, this is not the end of the story, so read the There's more... section.