create procedure with code below and call that procedure using

SQL> exec parent_child(table_name);

create or replace procedure parent_child(tname varchar2,p_chr varchar2 default '*') IS
 l_child varchar2(255):='';
 l_chr varchar2(255):='';
 l_tname varchar2(255):='';
 begin
 if p_chr='*' THEN
    dbms_output.put_line('Parent table'||chr(9)||chr(9)||'Child table');
 end if;
 for crec in (select * from user_constraints where table_name=tname
    and constraint_type='P') loop
    l_tname:=tname;
    for crec1 in
            (select * from user_constraints
                    where r_constraint_name=crec.constraint_name)
            loop
                    parent_child(crec1.table_name,'$');
                    IF length(l_child)>=1 THEN
                                    l_child:=l_child||','||crec1.table_name;
                    ELSE
                            l_child:=crec1.table_name;
                    END IF;
            end loop;
            IF length(l_child)>=1 THEN
                    dbms_output.put_line(l_tname||chr(9)||chr(9)||chr(9)||l_child);
            END IF;
    end loop;
 END;

Suresh Vemulapalli