pg_hashids: Short UIDs

pg_hashids provides a secure way to generate short, unique, non-sequential ids from numbers. The hashes are intended to be small, easy-to-remember identifiers that can be used to obfuscate data (optionally) with a password, alphabet, and salt. For example, you may wish to hide data like user IDs, order numbers, or tracking codes in favor of pg_hashid's unique identifiers.

Enable the extension

1
-- Enable the "pg_hashids" extension
2
create extension pg_hashids with schema extensions;
3
4
-- Disable the "pg_hashids" extension
5
drop extension if exists pg_hashids;

Usage

Suppose we have a table that stores order information, and we want to give customers a unique identifier without exposing the sequential id column. To do this, we can use pg_hashid's id_encode function.

1
create table orders (
2
  id serial primary key,
3
  description text,
4
  price_cents bigint
5
);
6
7
insert into orders (description, price_cents)
8
values ('a book', 9095);
9
10
select
11
  id,
12
  id_encode(id) as short_id,
13
  description,
14
  price_cents
15
from
16
  orders;
17
18
  id | short_id | description | price_cents
19
----+----------+-------------+-------------
20
  1 | jR       | a book      |        9095
21
(1 row)

To reverse the short_id back into an id, there is an equivalent function named id_decode.

Resources

• Official pg_hashids documentation