vb 为什么每次随机出来都是第一条记录

If db.State = adStateOpen Then
        db.Close
    End If
    rc.CursorLocation = 3
    db.Open "Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=courseexamine;Data Source=" + server_name
    rc.Open "select * from faultmanage ", db, adOpenDynamic, adLockOptimistic
      u = rc.RecordCount
          ReDim aryid(u)
      For z = 0 To rc.RecordCount - 1
        aryid(z) = Trim(rc("ID"))
      Next
      one = LBound(aryid)
      n = UBound(aryid)
   
      Randomize
      bx = Int(Rnd() * (Abs(n - one + 1)) + one)
     
    If db.State = adStateOpen Then
        db.Close
    End If
    db.Open "Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=courseexamine;Data Source=" + server_name
    rc.Open "select * from faultmanage where id ='" + Trim(aryid(bx)) + "'", db, adOpenDynamic, adLockOptimistic
    tm = Trim(rc("faultname"))
为什么每次随机出来的bx是对