Oracle/Sequence

Auto ID sequence:

--drop sequence mytable_seq;
create sequence mytable_seq;
create trigger mytable_seq before insert on mytable for each row
begin
   select mytable_seq.nextval into :new.ID from dual;
end;
/

Return new id after insert (PL/SQL):

declare
  i number;
begin
  insert into mytable (foo) values ('bar') returning id into i;
  insert into mytable_tags (i, tag) values ('tag 1');
  insert into mytable_tags (i, tag) values ('tag 2');
end;