用于在同一个表中插入记录的 INSERT 触发器

I have a trigger that is fire on inserting a new record in table in that i want to insert new record in the same table.
My trigger is :

create or replace trigger inst_table
after insert on test_table referencing new as new old as old  
for each row
declare 
      df_name varchar2(500);
      df_desc varchar2(2000);

begin
      df_name := :new.name;
      df_desc := :new.description;

     if inserting then
          FOR item IN (SELECT pid FROM tbl2 where pid not in(1))
             LOOP
                 insert into test_table (name,description,pid) values(df_name,df_desc,item.pid); 
             END LOOP;    
     end if; 
end;

它给出一个错误，如

ORA-04091:表 TEST_TABLE 正在变异，触发器/函数可能看不到它

我认为它阻止我插入同一张表.
那么如何将这条新记录插入到同一张表中.