คือผมอยากเก็บรหัสสินค้า conncept นี่ครับ ตอนนี้ใน db ผม เก็บรหัสแบบ auto increment อยู่ครับมันจะเป็น 1,2,3 ตามลำดับ

<?php
function convert_id($id , $length)
{
	$str = sprintf("P%0{$length}d",$id);
	return $str;
}
echo convert_id(1,5);
echo "<br />";
echo convert_id(350,5);
echo "<br />";
echo convert_id(999999,5);
?>

echo convert_id(1,5);
echo "<br />";
echo convert_id(350,5);
echo "<br />";
echo convert_id(999999,5);

$id=$result['s_id'];
$code=sprintf("P%04d",$id);

<? 
session_start();



$name=$_POST[name];  
$name2=$_POST[name2];  
$detail=$_POST[detail];  




include ("connect.php"); 



$sql ="insert into tb_type values ('  ','$name','$name2','$detail')"; 
$result =mysql_db_query($dbname,$sql);


if ($result) {
	echo"<meta http-equiv=\"refresh\" content=\"0;URL=type_show.php\" />";
	
} else {	

	echo "<script>alert(' ไม่สามารถเพิ่มประเภทสินค้าได้น่ะครับ ');history.back();</script>";
	echo"<meta http-equiv=\"refresh\" content=\"1;URL=type_show.php\" />";
}
mysql_close();
	
?>

<?php
	$dbhost = "localhost";
	$dbuser = "root";
	$dbpass = "";
	$GLOBALS['conn'] = mysql_connect($dbhost,$dbuser,$dbpass);
	
	mysql_select_db("mydatabase" , $GLOBALS['conn']);
	mysql_query("SET NAMES UTF8",$GLOBALS['conn']);
?>

<?php

	/**
	*	Represent Seed Entity.
	*/
	class Seed
	{
		/**
		*	Seed Id.
		*/
		private $id;
		
		/**
		*	Seed Fields Array.
		*/
		private $fields;

		/**
		*	Construction of Seed Class. Initialize method.
		*/
		public function __construct()
		{
			$this->id = NULL;
			$this->fields = array(
				"s_code" => "",
				"s_name" => "",
				"s_ename" => "",
				"s_origin" => "",
				"s_detail" => ""
				);
		}	// end of __construct method.

		/**
		*	Magic method set.
		*	@param $key Key of fields array.
		*	@param $value Value that you want to set properties value.
		*/
		public function __set($key , $value)
		{
			if(array_key_exists($key , $this->fields))
			{
				$this->fields[$key] = $value;
			}
		}	// end of __set method.
		
		/**
		*	Magic method get.
		*	@return (Mixed) Seed Field value.
		*/
		public function __get($key)
		{
			return $this->fields[$key];
		}	// end of __get method.
		
		/**
		*	Get Seed Class By id.
		*	@param $id Specify id of Seed.
		*	@return Seed obj which contain value from exist data in database. return FALSE if has not exist data.
		*/
		public function getById($id = 0)
		{			
			$sql = sprintf("SELECT * FROM Seed WHERE s_id = %d" , $id);
			$result = mysql_query($sql);
			if(mysql_num_rows($result))
			{
				$row = mysql_fetch_assoc($result);
				$obj = new Seed();
				$obj->id = $id;
				$obj->s_code = $row["s_code"];
				$obj->s_name = $row["s_name"];
				$obj->s_ename = $row["s_ename"];
				$obj->s_origin = $row["s_origin"];
				$obj->s_detail = $row["s_detail"];
				return $obj;
			}
			else
			{
				return FALSE;
			}
		}	// end of getById method.
		
		/**
		*	Check Exists Code of Seed.
		* 	@param $code Code of Seed
		*	@return TRUE if has exist code , FALSE if not found.
		*/
		public function isExistsCode($code)
		{
			$sql = sprintf("SELECT * FROM Seed WHERE s_code = '%s'", $code);
			$result = mysql_query($sql);
			if(mysql_fetch_array($result) > 0)
			{
				return TRUE;
			}
			else
			{
				return FALSE;
			}
		}	// end of isExistsCode method.
		
		/**
		*	Save Seed data to database. if not contain id do INSERT , else do UPDATE.
		*	@return TRUE if save successful . FALSE if error occured.
		*/
		public function save()
		{
			if($this->id == NULL)
			{
				$sql = sprintf("INSERT INTO seed(s_name , s_ename , s_origin , s_detail) ".
												 "VALUES('%s' , '%s' , '%s' , '%s' )",
												 $this->fields['s_name'],
												 $this->fields['s_ename'],
												 $this->fields['s_origin'],
												 $this->fields['s_detail']);
				mysql_query($sql);
				if(mysql_affected_rows() > 0)
				{
					$insert_id = mysql_insert_id();
					$code = Seed::getCode($insert_id);
					$sql = sprintf("UPDATE Seed SET s_code = '%s' WHERE s_id = %d", $code , $insert_id);
					mysql_query($sql);
					if(mysql_affected_rows() > 0)
					{
						return TRUE;
					}
					else
					{
						return FALSE;
					}
				}
				else
				{
					return FALSE;
				}
			}
			else
			{
				$sql = sprintf("UPDATE Seed SET s_code = '%s' , s_name = '%s' , s_ename = '%s' , s_origin = '%s' , s_detail = '%s' WHERE s_id = %d",
												 $this->fields['s_code'],
												 $this->fields['s_name'],
												 $this->fields['s_ename'],
												 $this->fields['s_origin'],
												 $this->fields['s_detail'],
												 $this->id);
				mysql_query($sql);
				if(mysql_affected_rows() > 0)
				{
					return TRUE;
				}
				else
				{
					return FALSE;
				}
			}
		}	// end of save method.
		
		public static function getCode($id = 0)
		{
			return sprintf("P%04d", $id);
		}
		
	} // end of Seed Class.
?>

<pre>
<?php
	require_once("include/dbconfig.php");
	require_once("class/Seed.php");
	
	// Insert date.
	$obj = new Seed();
	$obj->s_name = "name";
	$obj->s_ename = "ename";
	$obj->s_origin = "origin";
	$obj->s_detail = "detail";
	var_dump($obj->save());
	
	// Update data.
	$obj = Seed::getById(7);
	$obj->s_name = "name7";
	$obj->s_ename = "ename";
	$obj->s_origin = "origin";
	$obj->s_detail = "detail";
	var_dump($obj->save());
	
	// Check Exists Code.
	var_dump(Seed::isExistsCode("P0001"));
?>
</pre>