drop table audit_tbl
/
create table audit_tbl
(    timestamp    date,
    who            varchar2(30),
    tname        varchar2(30),
    cname        varchar2(30),
    old            varchar2(2000),
    new            varchar2(2000)
)
/

create or replace package audit_pkg
as
    procedure check_val( l_tname in varchar2, 
                             l_cname in varchar2, 
                 l_new in varchar2, 
                             l_old in varchar2 );

    procedure check_val( l_tname in varchar2, 
                             l_cname in varchar2, 
                     l_new in date, 
                             l_old in date );

    procedure check_val( l_tname in varchar2, 
                             l_cname in varchar2, 
                 l_new in number, 
                             l_old in number );
end;
/


create or replace package body audit_pkg
as

procedure check_val( l_tname in varchar2,
                     l_cname in varchar2,
             l_new in varchar2,
                     l_old in varchar2 )
is
begin
    if ( l_new <> l_old or
         (l_new is null and l_old is not NULL) or
         (l_new is not null and l_old is NULL) )
    then
        insert into audit_tbl values
        ( sysdate, sys_context('USERENV','OS_USER'), upper(l_tname), upper(l_cname),
                             l_old, l_new );
    end if;
end;

procedure check_val( l_tname in varchar2, l_cname in varchar2,
             l_new in date, l_old in date )
is
begin
    if ( l_new <> l_old or
         (l_new is null and l_old is not NULL) or
         (l_new is not null and l_old is NULL) )
    then
        insert into audit_tbl values
        ( sysdate, sys_context('USERENV','OS_USER'), upper(l_tname), upper(l_cname),
          to_char( l_old, 'dd-mon-yyyy hh24:mi:ss' ),
          to_char( l_new, 'dd-mon-yyyy hh23:mi:ss' ) );
    end if;
end;

procedure check_val( l_tname in varchar2, l_cname in varchar2,
             l_new in number, l_old in number )
is
begin
    if ( l_new <> l_old or
         (l_new is null and l_old is not NULL) or
         (l_new is not null and l_old is NULL) )
    then
        insert into audit_tbl values
        ( sysdate, sys_context('USERENV','OS_USER'), upper(l_tname), upper(l_cname),
                                 l_old, l_new );
    end if;
end;

end audit_pkg;
/