Associative Array to Nested Table: Anything faster?

Question

(First Post! Some ASP.NET references, but I think this really is a PL/SQL question)
I work on a team that runs an Oracle instance for data warehousing and reporting along with an ASP.NET based website for display.
Sometimes, I may want to have many parameters come in and only show records that match those parameters. For example, I may want to show all employees who are Managers or Developers and not show employees who are Accountants or Scientists. Typically, I send a parameter into my PL/SQL stored procedures as an associative array (as declared in my package specification). Once in the procedure, I convert that associative array into another associative array (as a user created SQL type) and then I'm able to use it like a nested table to join on.
My question is: in your experience, is there any way to get around this type conversion or another faster way?
For example:
-- Create the sql type
CREATE OR REPLACE TYPE DIM.sql_string_table AS TABLE OF VARCHAR2(255);
--pretend that this works and it's in a package body
declare
type string_table is table of varchar2(255) index by binary_integer;
l_job_types string_table; -- Keep in mind I'd normally be sending this via ASP.NET
l_job_types_nested sql_string_table := sql_string_table();
begin
-- Add some data
l_job_types(0) := 'Manager';
l_job_types(1) := 'Developer';
-- Do the conversion
for i in l_job_types.first .. l_job_types.last
loop
l_job_types_nested.extend;
l_job_types_nested(l_job_types_nested.count) := l_job_types(i);
end loop;
-- get some data out (we're pretending)
open fake_ref_cursor for
Select e.*
from employees e,
the(select cast(l_job_types_nested as sql_string_table) from dual) jobs_types_wanted
where e.type = value(jobs_types_wanted);
end;
The result would be all employees whose have a type that was input into the l_job_types associatve array.
See: http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:110612348061
for additional reference

Answer 1

> I convert that associative array into another associative array (as a user created SQL type)
Just so we're clear, Oracle use the term 'associative array' to refer to the exclusively PL/SQL sparse collection type ("table of x index by pls_integer" etc) as distinct from the common nested table collection type.
Also I could be wrong but I think
SELECT ..
FROM   the(select cast(l_job_types_nested as sql_string_table) from dual) jobs_types_wantedis generally the same as
SELECT ..
FROM   TABLE(l_job_types_nested) jobs_types_wantedthough "SELECT *" and implicitly collection casting don't always mix. The "THE()" syntax is deprecated.