SQL & PL/SQL :: Dynamic Where Clause

I having below table :

EXAM2@orcl> desc search_table;
Name Null? Type
----------------------------------------- -------- ----------------------------
ROL NOT NULL VARCHAR2(7)
CNM NOT NULL VARCHAR2(30)
FNM NOT NULL VARCHAR2(30)
MNM NOT NULL VARCHAR2(30)
DOB NOT NULL DATE
YEAR NOT NULL NUMBER(4)
EXAM NOT NULL VARCHAR2(1)
MAIN_SUPP NOT NULL VARCHAR2(1)

In a dotnet application user is going to input/select all/any of the above column in where clause.If user has given value for rol column then ref cursor should be :

select * from search_table where rol like <given value>
endif
and/or

If user has given value for cnm column then ref cursor should be :

select * from search_table where rol like <given value> and/or cnm like <given value>
endif

I mean whatever value is being given; it should be part of where clause.For it i am going to :

EXAM2@orcl> CREATE OR REPLACE PACKAGE rollsearch AS
2 TYPE t_cursor IS REF CURSOR;
3 Procedure rol_cursor(c_rol in varchar2,c_cnm in varchar2,c_fnm in varchar2,
4 c_mnm in varchar2,d_dob in date,n_year in number,c_exam in varchar2,c_main_supp in varchar2,
5 io_cursor IN OUT t_cursor);
6 END rollsearch;
7 /

EXAM2@orcl> CREATE OR REPLACE PACKAGE BODY rollsearch AS
2 Procedure rol_cursor(c_rol in varchar2,c_cnm in varchar2,c_fnm in varchar2,
3 c_mnm in varchar2,d_dob in date,n_year in number,c_exam in varchar2,c_main_supp in varchar2,
4 io_cursor IN OUT t_cursor)
5 IS
6 v_cursor t_cursor;
7 sql varchar2(1000);
8 BEGIN
9

What should i write further; so that i may get ref cursor as whereed clause for given value. So that i may populate my datagrid view for that web form.