[Pseudo random integer generator] Create pseudo random integer from sequence ([from Postgres wiki](https://wiki.postgresql.org/wiki/Pseudo_encrypt)) #sql #database

pseudo-random-integer.sql

create sequence testes.test_id_seq
;

create or replace function pseudo_encrypt(value int) returns int as $$
declare
l1 int;
l2 int;
r1 int;
r2 int;
i int:=0;
begin
 l1:= (value >> 16) & 65535;
 r1:= value & 65535;
 while i < 3 loop
   l2 := r1;
   r2 := l1 # ((((1366 * r1 + 150889) % 714025) / 714025.0) * 32767)::int;
   l1 := l2;
   r1 := r2;
   i := i + 1;
 end loop;
 return ((r1 << 16) + l1);
end;
$$ language plpgsql strict immutable;

create table testes.id_test (
test_uid uuid not null default uuid_generate_v4(),
id varchar not null default concat('sp', lpad(pseudo_encrypt(nextval('testes.test_id_seq')::int)::text, 10, '0'))
);