ช่วยผมแก้โค้ด random เลขบทและข้ออัตโนมัติหน่อยครับ

$sql = "select count(Exname) as cid from tbexamination where Unit_id= ".$row["Unit_id"];
$resultCat = mysqli_query($dblink, $sql);
$rows=mysqli_fetch_array($resultCat,MYSQL_ASSOC);
$no = $rows["cid"]+1;
mysqli_close($dblink);
if($_GET["mode"]=="cancel"){
	unset($_SESSION["arrData"]);
}
if(isset($_SESSION["arrData"])){
	$inputData = $_SESSION["arrData"];
}
if($rowsCat > 0){ ?>
	<form action="ONLINE_insertProcess.php" method="post" enctype="multipart/form-data">
		<table align="center" bgcolor="#FFCC00" width="60%" border="0" style="font-weight:bold; color:#666666">
			<tr align="center"  height="30" style="color:#FFFFFF">
				<td colspan="2"><img src="images/pass4.png" width="700" height="50"></a></td>
			</tr>
						<tr bgcolor="#FFFFCC">
				<td width="20%"><font size="2" face="COPRGTB">&nbsp;&nbsp;&nbsp; บทที่</font></td>
				<td width="60%">&nbsp;&nbsp;&nbsp;<input type="text" name="txtUnit" value="<? echo $row["Unit_id"];?>"size="20"></td>
			</tr>
			<tr bgcolor="#FFFFCC">
				<td width="20%"><font size="2" face="COPRGTB">&nbsp;&nbsp;&nbsp; ข้อ</font></td>
				<td width="60%">&nbsp;&nbsp;&nbsp;<input type="text" name="txtExname" value="<? echo $no["cid"];?>"size="20"></td>
			</tr>