PHP网页设计PHP/MySQL 购物车法式

既然选择了PHP，就要坚持学下去！大家有没有问自己为什么会选择学习PHP呢？就我个人而言，完全是因为兴趣，因为我的专业和计算机完全无关，但是就是对编程很赶兴趣，尤其对网络编程、web开发特别赶兴趣。   

     <?
  if(!$session && !$scid) {
  $session = md5(uniqid(rand()));
  SetCookie("scid", "$session", time() + 14400);
  } /* last number is expiration time in seconds, 14400 sec = 4 hrs */
   
  class Cart {
  function check_item($table, $session, $product) {
  $query = "SELECT * FROM $table WHERE session='$session' AND product='$product' ";
  $result = mysql_query($query);
   
  if(!$result) {
  return 0;
  }
   
  $numRows = mysql_num_rows($result);
   
  if($numRows == 0) {
  return 0;
  } else {
  $row = mysql_fetch_object($result);
  return $row->quantity;
  }
  }
   
  function add_item($table, $session, $product, $quantity) {
  $qty = $this->check_item($table, $session, $product);
  if($qty == 0) {
  $query = "INSERT INTO $table (session, product, quantity) VALUES ";
  $query .= "('$session', '$product', '$quantity') ";
  mysql_query($query);
  } else {
  $quantity += $qty;
  $query = "UPDATE $table SET quantity='$quantity' WHERE session='$session' AND ";
  $query .= "product='$product' ";
  mysql_query($query);
  }
  }
   
  function delete_item($table, $session, $product) {
  $query = "DELETE FROM $table WHERE session='$session' AND product='$product' ";
  mysql_query($query);
  }
   
  function modify_quantity($table, $session, $product, $quantity) {
  $query = "UPDATE $table SET quantity='$quantity' WHERE session='$session' ";
  $query .= "AND product='$product' ";
  mysql_query($query);
  }
   
  function clear_cart($table, $session) {
  $query = "DELETE FROM $table WHERE session='$session' ";
  mysql_query($query);
  }
   
  function cart_total($table, $session) {
  $query = "SELECT * FROM $table WHERE session='$session' ";
  $result = mysql_query($query);
  if(mysql_num_rows($result) > 0) {
  while($row = mysql_fetch_object($result)) {
  $query = "SELECT price FROM inventory WHERE product='$row->product' ";
  $invResult = mysql_query($query);
  $row_price = mysql_fetch_object($invResult);
  $total += ($row_price->price * $row->quantity);
  }
  }
  return $total;
  }
   
  function display_contents($table, $session) {
  $count = 0;
  $query = "SELECT * FROM $table WHERE session='$session' ORDER BY id ";
  $result = mysql_query($query);
  while($row = mysql_fetch_object($result)) {
  $query = "SELECT * FROM inventory WHERE product='$row->product' ";
  $result_inv = mysql_query($query);
  $row_inventory = mysql_fetch_object($result_inv);
  $contents["product"][$count] = $row_inventory->product;
  $contents["price"][$count] = $row_inventory->price;
  $contents["quantity"][$count] = $row->quantity;
  $contents["total"][$count] = ($row_inventory->price * $row->quantity);
  $contents["description"][$count] = $row_inventory->description;
  $count++;
  }
  $total = $this->cart_total($table, $session);
  $contents["final"] = $total;
  return $contents;
  }
   
  function num_items($table, $session) {
  $query = "SELECT * FROM $table WHERE session='$session' ";
  $result = mysql_query($query);
  $num_rows = mysql_num_rows($result);
  return $num_rows;
  }
   
  function quant_items($table, $session) {
  $quant = 0;
  $query = "SELECT * FROM $table WHERE session='$session' ";
  $result = mysql_query($query);
  while($row = mysql_fetch_object($result)) {
  $quant += $row->quantity;
  }
  return $quant;
  }
  }
  ?>
   
  /*
  This part contains a description of how to create the tables on your mysql server.
   
  # MySQL dump 6.0
  #
  # Host: localhost Database: kmartShopper
  #--------------------------------------------------------
  # Server version 3.22.25
   
  #
  # Table structure for table 'inventory'
  #
  CREATE TABLE inventory (
  product tinytext NOT NULL,
  quantity tinytext NOT NULL,
  id int(4) DEFAULT '0' NOT NULL auto_increment,
  description tinytext NOT NULL,
  price float(10,2) DEFAULT '0.00' NOT NULL,
  category char(1) DEFAULT '' NOT NULL,
  KEY id (id),
  PRIMARY KEY (id),
  KEY price (price)
  );
   
  #
  # Table structure for table 'shopping'
  #
  CREATE TABLE shopping (
  session tinytext NOT NULL,
  product tinytext NOT NULL,
  quantity tinytext NOT NULL,
  card tinytext NOT NULL,
  id int(4) DEFAULT '0' NOT NULL auto_increment,
  KEY id (id),
  PRIMARY KEY (id)
  );
  */
   
  Example
  <?
  include("shoppingcart.php");
  $cart = new Cart;
  $mysql_link = mysql_connect("localhost", "wwwrun", "");
  $mysql_select_db("kmartShopper", $mysql_link) /* heh, use whatever database name you put the 2 tables under in place of kmartShopper */
  ?>
  /* call functions like $cart->add_item and such, see the code. */
   
  
不过还好，PHP语言给出的语法错误很详细，只要稍微熟悉一点之后，看错误提示就能很容易找出错误所在的。PHP还有一个特别好用的调试功能，在PHP语句中，你可以随时用echo来输出结果。