Wie eindeutige Rechnungsnummer in DB erstellen und speichern?

[jobo]

Code:

insert into mytable 
values (1,                                                                        -- id
        'rn#_'||CAST(Extract(year  FROM cast('NOW' as date))*10000 +
                     Extract(month FROM cast('NOW' as date))*100 +
                     Extract(day   FROM cast('NOW' as date)) AS VARCHAR(8))||
        LPAD (gen_id(gen_rn,1), 6, '0'),                                          -- rechnungsnummer 
        cast('Now' as date));                                                     -- date

und reset

Code:

set generator gen_rn to 0;