Question

我的dbMySql.PHP文件编码

<?php
define('DB_SERVER','localhost');
define('DB_USER','root');
define('DB_PASS' ,'');
define('DB_NAME', 'dbtuts');

class DB_con
{
 function __construct()
 {
 global $conn;
 $conn = mysql_connect(DB_SERVER,DB_USER,DB_PASS) or die('localhost connection problem'.mysql_error());
  mysql_select_db(DB_NAME);
 }
 public function insert($fname,$lname,$city)
 {
  $sql = "INSERT users(first_name,last_name,user_city)VALUES('$fname','$lname','$city')";
  $res = mysql_query($sql);
  return $res;
 }
 public function select()
 {
    // $db=new DB_con();
   //  $db->__construct();
   $sql = "SELECT * FROM users";
   $res=mysql_query($sql);

    // return $conn;
   return $res;
 }
}
?>

我的index.php文件

<?php
include_once 'dbMySql.php';
$con = new DB_con();
$table = "users";
$res=$con->select($table);
?>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
<link rel="stylesheet" href="style.css" type="text/css" />
</head>
<body>
<center>
<div id="header">
 <div id="content">
    <label></label>
    </div>
</div>
<div id="body">
 <div id="content">
    <table align="center">
    <tr>
    <th colspan="3"><a href="add_data.php">ADD</a></th>
    </tr>
    <tr>
    <th>First Name</th>
    <th>Last Name</th>
    <th>City</th>
    </tr>
    <?php
 while($row=mysql_fetch_row($res))
 {
   ?>
            <tr>
            <td><?php echo $row[1]; ?></td>
            <td><?php echo $row[2]; ?></td>
            <td><?php echo $row[3]; ?></td>
            </tr>
            <?php
 }
 ?>
    </table>
    </div>
</div>

<div id="footer">
 <div id="content">
    <hr /><br/>
    <label>Appxone Private Limited<a href="http://cleartuts.blogspot.com"></a></label>
    </div>
</div>

</center>
</body>
</html>

我的add_data.php文件编码

<?php
include_once 'dbMySql.php';
$con = new DB_con();

// data insert code starts here.
if(isset($_POST['btn-save']))
{
 $fname = $_POST['first_name'];
 $lname = $_POST['last_name'];
 $city = $_POST['city_name'];

 $res=$con->insert($fname,$lname,$city);
 if($res)
 {
  ?>
  <script>
  alert('Record inserted...');
        window.location='index.php'
  </script>
  <?php
 }
 else
 {
  ?>
  <script>
  alert('error inserting record...');
        window.location='index.php'
        </script>
  <?php
 }
}
// data insert code ends here.

?>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>PHP Data Insert and Select Data Using OOP - By Cleartuts</title>
<link rel="stylesheet" href="style.css" type="text/css" />
</head>
<body>
<center>

<div id="header">
 <div id="content">
    <label>PHP Data Insert and Select Data Using OOP - By Cleartuts</label>
    </div>
</div>
<div id="body">
 <div id="content">
    <form method="post">
    <table align="center">
    <tr>
    <td><input type="text" name="first_name" placeholder="First Name" required /></td>
    </tr>
    <tr>
    <td><input type="text" name="last_name" placeholder="Last Name" required /></td>
    </tr>
    <tr>
    <td><input type="text" name="city_name" placeholder="City" required /></td>
    </tr>
    <tr>
    <td>
    <button type="submit" name="btn-save"><strong>SAVE</strong></button></td>
    </tr>
    </table>
    </form>
    </div>
</div>

</center>
</body>
</html>

我的style.css编码

@charset "utf-8";
/* CSS Document */

*
{
 margin:0;
 padding:0;
}
#header
{
 width:100%;
 height:50px;
 background:#00a2d1;
 color:#f9f9f9;
 font-family:"Lucida Sans Unicode", "Lucida Grande", sans-serif;
 font-size:35px;
 text-align:center;
}
#header a
{
 color:#fff;
 text-decoration:blink;
}
#body
{
 margin-top:50px;
}
table
{
 width:40%;
 font-family:Tahoma, Geneva, sans-serif;
 font-weight:bolder;
 color:#999;
 margin-bottom:80px;
}
table a
{
 text-decoration:none;
 color:#00a2d1;
}
table,td,th
{
 border-collapse:collapse;
 border:solid #d0d0d0 1px;
 padding:20px;
}
table td input
{
 width:97%;
 height:35px;
 border:dashed #00a2d1 1px;
 padding-left:15px;
 font-family:Verdana, Geneva, sans-serif;
 box-shadow:0px 0px 0px rgba(1,0,0,0.2);
 outline:none;
}
table td input:focus
{
 box-shadow:inset 1px 1px 1px rgba(1,0,0,0.2);
 outline:none;
}
table td button
{
 border:solid #f9f9f9 0px;
 box-shadow:1px 1px 1px rgba(1,0,0,0.2);
 outline:none;
 background:#00a2d1;
 padding:9px 15px 9px 15px;
 color:#f9f9f9;
 font-family:Arial, Helvetica, sans-serif;
 font-weight:bolder;
 border-radius:3px;
 width:100%;
}
table td button:active
{
 position:relative;
 top:1px;
}
#footer
{
 margin-top:50px;
 position:relative;
 bottom:30px;
 font-family:Verdana, Geneva, sans-serif;
}

所有代码都正常工作并且数据插入成功并显示但是如果你看到上面的第一个文件我正在使用mysql，我想使用mysqli但问题是当show $ conn作为全局变量时（因为mysqli需要2个参数）和在mysqli中使用（$ sql，$ conn），错误显示未定义变量$ conn为什么？

Answer 1

将$ this用于班级中的访问变量

define('DB_SERVER','localhost');
define('DB_USER','root');
define('DB_PASS' ,'');
define('DB_NAME', 'dbtuts');

class DB_con {
    private $conn;
    function __construct() {
        $this->conn = mysqli_connect(DB_SERVER,DB_USER,DB_PASS) or die('localhost connection problem'.mysql_error());
        mysqli_select_db($this->conn, DB_NAME);
    }
    public function insert($fname,$lname,$city) {
        $sql = "INSERT users(first_name,last_name,user_city)VALUES('$fname','$lname','$city')";
        $res = mysqli_query($this->conn, $sql);
        return $res;
    }
    public function select() {
        // $db=new DB_con();
        //  $db->__construct();
        $sql = "SELECT * FROM users";
        $res = mysqli_query($this->conn, $sql);

        // return $conn;
        return $res;
    }
}

全局变量在另一个函数中不起作用的原因

1 个答案: