Re: Best way to insert a row with two columns having the value based on the same argument generated by another postgres function.

On Thu, Jul 7, 2016 at 2:56 AM, Silk Parrot <silkparrot(at)gmail(dot)com> wrote:

> Hi,
>
> I am trying to build a user database. The steps for creating a new user
> are:
>
> 1. Use gen_salt to create a salt.
> 2. Compute the hash based on the salt and password and store both the hash
> and the salt into a new row.
>
>
> The pl/pgsql would look like this:
>
> CREATE OR REPLACE FUNCTION system.create_enduser(IN emailArg TEXT, IN passwordArg TEXT, IN nicknameArg TEXT, IN roundsArg int) RETURNS TEXT AS
> $$
> #print_strict_params on
> DECLARE
> salt TEXT;
> inserted_uuid TEXT;
> BEGIN
> salt := public.gen_salt('bf', roundsArg);
> INSERT INTO system.enduser (email, password_hash, password_salt, nickname, user_state) VALUES (emailArg, public.crypt(passwordArg, salt), salt, nicknameArg, 'REGISTERED') RETURNING uuid into inserted_uuid;
> RETURN inserted_uuid;
> END
> $$
> LANGUAGE 'plpgsql' VOLATILE
> ;
>
>
> Is there a way to do this in a single SQL statement without using a
> function? One way I can think of is using trigger, but that still requires
> another setup.
>
> Appreciate any help.
>

​WITH salt_value AS (
SELECT gen_salt('bf', roundsArg) AS value_of_salt
)​

​INSERT INTO system.enduser
SELECT emailArg, crypt(passwordArg, value_of_salt), value_of_salt, ...
FROM salt_value​;

You can probably lose the WITH and just make a subquery FROM...

David J.