How to implement invoker rights in oracle 9i

Question

implement invoker rights in oracle 9i

Answer 1

Invoker rights is a new model for resolving references to database elements in a PL/SQL program unit. From Oracle 8i onwards, we can decide if a program unit should run with the authority of the definer or of the invoker. This means that multiple schemas, accessing only those elements belonging to the invoker, can share the same piece of code.
To enable code to run with Invoker rights, an AUTHID clause needs to be used before the IS or AS keyword in the routine header. The AUTHID clause tells Oracle whether the routine is to be run with the invoker rights (CURRENT_USER), or with the Owner rights (DEFINER). If you do not specify this clause, Oracle by default assumes it to be AUTHID DEFINER.
create or replace procedure update_par(pi_parcod  in     varchar2,
                                       pi_val     in     varchar2,
                                       pio_status in out varchar2)
authid current_user is
begin
  pio_status = 'OK';
  update appparmst
  set    parval = pi_val
  where  parcod = pi_parcod
  and    rownum = 1;
  if sql%notfound then
    pio_status = 'Error in resetting the parameter';
  end if;
end; Restriction in using Invoker rights
1. When compiling a new routine, direct privileges are only considered to resolve any external references. Grants through roles are ignored. The same applies when executing a routine created with invoker rights.
2. AUTHID is specified in the header of a program unit. The same cannot be specified for individual programs or methods within a package or object type.
3. Definer rights will always be used to resolve any external references when compiling a new routine.
4. Maintain extra caution on privileges being assigned to a different user. If the wrong privileges are assigned, a routine with invoker rights may have a mind of its own! Such issues would be difficult to debug. So ensure that the grants are perfectly in place.
5. For an invoker rights routine referred in a view or a database trigger, the owner of these objects is always considered as the invoker, and not the user triggering it.
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