PHP实战：PHP MYSQL简易交互式站点开发

<center>
 <form method="post" action="<?php echo $_SERVER['SCRIPT_NAME'] ?>">
 用户名: <input type="text" name="user_name">
 密码: <input type="text" name="password">
 <input type="Submit" name="submit" value="登陆">
 </form>
</center>

//登陆处理
 if (isset($_POST['submit'])) 
 {
  // 用户名输入为空
  if($_POST['user_name'] == '')
  // 调用javascript函数动态提醒
  echo "<script type='text/javascript'>dis_alert(\"用户名\",1);</script>";// 密码输入为空
  if($_POST['password'] == '')
  // 调用javascript函数动态提醒
  echo "<script type='text/javascript'>dis_alert(\"密码\",1);</script>";
  // 用户名与密码均不为空
  $user_name = $_POST['user_name'];
  //链接数据库,从中读出用户名和密码
  $db = mysql_connect("localhost", "root", "123456");
  mysql_select_db("linyimin", $db);
  $result = mysql_query("select * from login where user_name = '$user_name'");
  $num = mysql_num_rows($result);
  //判断用户输入的用户名存在,验证密码
  if($num != 0)
  {
  $user_name = mysql_result($result,0,'user_name');
  $password = mysql_result($result,0,'password');
  if(strcmp($password,$_POST['password']) != 0)
  {
   echo "密码错误";
   //密码错误,报错
   $password = $_POST['password'];
   echo "<script type='text/javascript'>dis_alert('密码错误',3);</script>";
  }
  // 密码正确
  else
  {
   session_unset();
   session_start();
   $_SESSION['user_name'] = $_POST[user_name];
   header("Location:http://localhost/display.php");
   exit;
  }
  }
  // 用户输入的用户名不存在,报错 
  else if($num == 0)
  {
  // 用户名不存在,报错
  $user_name = $_POST['user_name'];
  echo "<script type='text/javascript'>dis_alert(\"$user_name\",2);</script>";
  }
  mysql_close($db); 
 }//登陆处理结束

<script type="text/javascript">
// 登陆错误提醒
function dis_alert(var1, var2)
{
 // 用户名和密码不能为空提醒
 if(var2 == 1)
 {
 alert(var1 + " 不能为空,请重新输入");
 history.back(-1);
 }
 // 用户名不存在错误提醒
 if(var2 == 2)
 {
 alert("该用户名 " + var1 + " 不存在,请重新输入");
 history.back(-1);
 }
 // 密码错误提醒
 if(var2 == 3)
 {
 alert("密码错误,请重新输入");
 history.back(-1);
 }
}
</script>

// 获取登陆名
session_start();
$NAME = $_SESSION['user_name'];
// 连接数据库,获取数据并显示
function display()
{
 global $NAME;
 $db = mysql_connect("localhost", "root", "123456");
 mysql_select_db("linyimin",$db);
 $sql = "select * from admin_info";
 $result = mysql_query($sql);
 // 显示信息表
 echo "<h3 align=right color=#FFFFFF> 当前用户:$NAME</h6>";
 echo "<table border = 0 align = center width = 1000></br>";
 // 添加超链接
 echo "<tr align = center><th> <a href =\"display.php?add=yes\">ADD</a></th><br>";
 // 修改添加超连接
 echo "<th> <a href =\"display.php?update=yes\">UPDATE</a></th><br>";
 // 删除超链接
 echo "<th> <a href =\"display.php?delete=yes\">DELETE</a></th></tr><br>";
 echo "</table>";
 echo "<table border = 2 align = center width = 1000></br>";
 // 表头
 echo "<tr><th colspan=\"3\">管理员权限表</th></tr><br>";
 echo "<tr align = center><td>姓名</td><td>权限</td><td>职务</td></tr><br>";
 while($row = mysql_fetch_row($result))
 {
 // 显示管理员信息并通过超链接调用处理函数
 echo "<tr align = center><td>$row[0]</td>";
 echo "<td>$row[1]</td>";
 echo "<td>$row[2]</td></tr>";
 }
 echo "</table>";
 mysql_close($db);
}

<center>
 <form method="post" action="<?php echo $_SERVER['URL'] ?>">
 姓名: <input type="text" name="user_name">
 权限: <input type="text" name="pemission">
 职务: <input type="text" name="position">
 <input type="Submit" name="update" value="提交">
 </form>
</center>

 <center> 
 <form method="post" action="<?php echo $_SERVER['URL'] ?>" onsubmit="return confirm('请确认删除');">
 姓名: <input type="text" name="user_name">
 <input type="submit" name="update" value="删除">
</center>

// 调用修改函数
if ($_GET[update]) 
{
 modify("update");
}
// 调用添加函数
elseif($_GET[add])
{
 modify("add");
}
elseif($_GET[delete])
{
 modify("delete");
}

// 修改数据函数
/*
点击修改超链接,跳转到修改页面
表单中,名字项指定要修改记录
权限和职务项为可修改内容
*/
function modify($operation)
{
 if(isset($_POST['update']))
 {
 // 有root权限修改,修改
 if($operation == "update" && judge("update"))
 {
  $user_name = $_POST[user_name];
  $sql = "UPDATE admin_info SET pemission = '$_POST[pemission]', position ='$_POST[position]' WHERE user_name = '$user_name'";
  mysql_query($sql);
  mysql_close($db);
  display();
 }
 // 添加
 elseif(judge("add") && $operation == "add")
 {
  $user_name = $_POST[user_name];
  $sql = "insert into admin_info (user_name, pemission, position) values ('$_POST[user_name]','$_POST[pemission]','$_POST[position]')";
  mysql_query($sql);
  mysql_close($db);
  display();
 }
 // 删除
 elseif(judge("delete") && $operation == "delete")
 {
  $user_name = $_POST[user_name];
  // 获取确认情况
  $sql = "delete from admin_info where user_name = \"$user_name\"";
  mysql_query($sql);
  }
 }
}

// 判断修改用户名是否存在和该用户是否具有权限
function judge($operation)
{
 global $NAME;
 // 修改用户名
 $user_name = $_POST['user_name'];
 // 连接数据库,获取数据
 $db = mysql_connect("localhost", "root", "123456");
 mysql_select_db("linyimin",$db);
 // 该用户是否存在
 $sql = "select * from admin_info where user_name = \"$user_name\"";
 $result = mysql_query($sql);
 $num = mysql_num_rows($result);
 // 输入名称不存在
 if ($num == 0 && $operation != "add")
 {
  $user_name = $_POST['user_name'];
  echo "<script type='text/javascript'>dis_alert(\"$user_name\",2);</script>";
  return 0;
 }
 else
 {
  // 判断有没有权限(只有root权限可以修改)
  $sql = "select * from admin_info where user_name = \"$NAME\"";
  $result = mysql_query($sql);
  $pemission = mysql_result($result,0,'pemission');
  // 没有root权限,报错
  if(strcmp($pemission,"root") != 0)
  {
  $user_name = $_POST['user_name'];
  echo "<script type='text/javascript'>dis_alert(\"$user_name\",1);</script>";
  return 0;
  }
  else 
  return 1;
 } 
}

usersession_unset();
session_start();
$_SESSION['变量名'] = "值";

session_start();
$NAME = $_SESSION['变量名'];

// 连接数据库
$db = mysql_connect("url", "用户名", "密码");
// 选择数据库
mysql_select_db("数据库名称",$db);

$sql = "select * from admin_info where 字段名 = \"查找值\"";
$result = mysql_query($sql);
// 对查找返回结果进行操作
// 获取查找返回记录数条数
$num = mysql_num_rows($result);
// 获取查找结果第一条记录的user_name字段值
$user_name = mysql_result($result,0,'user_name');
// 逐条取出查询记录
while($row = mysql_fetch_row($result))
{
 相关操作；
}

$sql = "insert into 数据表 (字段1, 字段2, 字段3) values ('值1','值2','值3')";
mysql_query($sql);

$sql = "delete from 数据表 where 字段名 = \"查找值\"";
mysql_query($sql);
// 关闭数据库
mysql_close($db);

<?php
echo "<script type='text/javascript'>javascript函数;</script>";
?>