create table books(k serial primary key, doc jsonb not null);

insert into books(doc) values
  ('
    { "ISBN"    : 4582546494267,
      "noscript"   : "Macbeth",
      "author"  :
        {"given_name": "William",
         "family_name": "Shakespeare"},
      "year"    : 1623
    }
  ');

alter table books
add constraint books_doc_is_object
check(
  jsonb_typeof(doc) is not null and
  jsonb_typeof(doc) = 'object'
);

alter table books
add constraint books_doc_isbn_ok
check(
  doc->>'ISBN' is not null              and
  jsonb_typeof(doc->'ISBN') = 'number'  and
  (doc->>'ISBN')::bigint > 0            and
  length(doc->>'ISBN') = 13
);

SELECT DISTINCT
    a.amname
FROM
    pg_type t
    JOIN pg_opclass o ON o.opcintype = t.oid
    JOIN pg_am a ON a.oid = o.opcmethod
WHERE
    t.typname = 'int4';
 
 amname 
--------
 btree
 hash
 brin
(3 rows)