PHP學習練手（十一）
阿新 • • 發佈：2018-12-25
給指令碼傳值
1、方法一：利用HTML的隱藏輸入框型別
<input type="hidden" name="do" value="this" />在提交form表單時，$_POST[‘do’]將具有this這個值（假定表單使用POST方式）
2、把值追加到URL上
www.example.com/page.php?do=this這種方式模仿了html表單的GET方法。
3、view_user3.php——該指令碼能夠展示Edit和Delete連結，並在每個url中傳遞一起傳遞使用者的ID號
<?php #Script 9.4 -view_users.php 執行後：
知識點：
為了把多個變數追加到URL中，可以使用下面這種語法：page.php?name1=value?&name2=value2&name3=value3…
新增變數到url中的一種技巧是應該對字串編碼。以確保值會被正確處理。解決方案是使用urlencode()函式：
$url = ‘page.php?’.urlencode(‘Elli Simth’);
單提交表單時，GET方式會自動正確的執行。
4、delete_user.php——使用隱藏的表單輸入框
<?php # Script 10.2 - delete_user.php
$page_title = 'Delete a User';
include ('../include/header.html');
echo '<h1>Delete a User</h1>';
if((isset($_GET['id'])) && (is_numeric($_GET['id'])))
{
$id = $_GET['id'];
}elseif((isset($_POST['id'])) && (is_numeric($_POST['id'])))
{
$id = $_POST['id'];
}else{
echo '<p class="error">This page has been accessed in error.</p>';
exit();
}
require_once('../mysqli_connect.php');
if($_SERVER['REQUEST_METHOD'] == 'POST')
{
if($_POST['sure'] == 'Yes')
{
$sql = "DELETE FROM users WHERE user_id=$id LIMIT 1";
$res = @mysqli_query($mysqli, $sql);
if(mysqli_affected_rows($mysqli) == 1)
{
echo '<p>The user has been deleted</p>';
}else{
echo '<p class="error">The user could not be deleted due to a system.</p>';
echo '<p>'.mysqli_error($mysqli).'<br/ >Query:'.$sql.'</p>';
}
}else{
echo '<p>The user has NOT been deleted.</p>';
}
}else{
$sql = "SELECT CONCAT(last_name, ',', first_name) FROM users WHERE user_id = $id";
$res = @mysqli_query($mysqli, $sql);
if(mysqli_num_rows($res) == 1)
{
$row = mysqli_fetch_array($res, MYSQLI_NUM);
echo "<h3>Name: $row[0]</h3>
Are you sure you want to delete this user?";
echo '<form action="delete_user.php" method="post">
<input type="radio" name="sure" value="Yes"/>Yes
<input type="radio" name="sure" value="No" checked="checked"/>No
<input type="submit" name="submit" value="Submit"/>
<input type="hidden" name="id" value="'.$id.'"/>
</form>';
}else{
echo '<p class="error">This page has been accessed in error.</p>';
}
}
mysqli_close($mysqli);
include('../include/footer.html');
?>當從如下圖所示頁面進入delete_user.php，會出現：
原因如下：
if((isset($_GET['id'])) && (is_numeric($_GET['id'])))
{
$id = $_GET['id'];
}elseif((isset($_POST['id'])) && (is_numeric($_POST['id'])))
{
$id = $_POST['id'];
}else{
echo '<p class="error">This page has been accessed in error.</p>';
exit();
}由於這種進入方式並沒有提交表單，故直接進入到報錯的echo中。。。
當從view_users3.php進入時，如下：
選擇No，提交：
選擇Yes，提交：
5、edit_user.php
<?php
$page_title = 'Edit a User';
include ('../include/header.html');
echo '<h1>Edit a User</h1>';
if((isset($_GET['id'])) && (is_numeric($_GET['id'])))
{
$id = $_GET['id'];
}elseif((isset($_POST['id'])) && (is_numeric($_POST['id'])))
{
$id = $_POST['id'];
}else{
echo '<p class="error">This page has been accessed in error.</p>';
exit();
}
require_once('../mysqli_connect.php');
if($_SERVER['REQUEST_METHOD'] == 'POST')
{
$errors = array();
//檢查first name
if(empty($_POST['first_name']))
{
$errors[] = 'You forgot to enter your first name';
}else{
$fn = mysqli_real_escape_string($mysqli, trim($_POST['first_name']));
}
//檢查last name
if (empty($_POST['last_name']))
{
$errors[] = 'You forgot to enter your last name';
}else{
$ln = mysqli_real_escape_string($mysqli, trim($_POST['last_name']));
}
//檢查email Address
if (empty($_POST['email']))
{
$errors[] = 'You forgot to enter your email';
}else{
$e = mysqli_real_escape_string($mysqli, trim($_POST['email']));
}
if(empty($errors))
{
$sql = "SELECT user_id FROM users WHERE email= '$e' AND user_id != '$id'"; //判斷提交的電子郵件地址是否尚未使用
$res = @mysqli_query($mysqli, $sql);
if(mysqli_num_rows($res) == 0)
{//若表中不存在該郵件使用者的ID,表明郵件尚未使用
$sql = "UPDATE users SET first_name= '$fn', last_name= '$ln', email= '$e' WHERE user_id= $id LIMIT 1";
$res = @mysqli_query($mysqli, $sql);
if(mysqli_affected_rows($mysqli) == 1) //受影響記錄條數
{
echo '<p>The user has been edited.</p>';
}else{
echo '<p>The user could not be edited due to a system error. We apologize for any inconvenience</p>';
echo '<p>'.mysqli_error($mysqli).'<br /><br />'.$sql.'</p>';
}
}else{
echo '<p>The email address has been already been registered.</p>';
}
}//if_$errors
else{
echo '<h1>Error!</h1>
<p class="error">The following error(s) occured:<br/ >';
foreach ($errors as $msg) {
echo "- $msg<br/ >";
}
echo '</p><p>Please try again</p><p><br/ ></p>';
}
}
$sql = "SELECT first_name, last_name, email FROM users WHERE user_id = $id";
$res= @mysqli_query($mysqli, $sql);
if(mysqli_num_rows($res) == 1) //有效的使用者ID
{
$rows = mysqli_fetch_array($res, MYSQLI_NUM);
echo '<form action="edit_user.php" method="post">
<p>First Name: <input type="text" name="first_name" size="15" maxlength="15" value="'.$rows[0].'"/></p>
<p>Last Name: <input type="text" name="last_name" size="15" maxlength="30" value="'.$rows[1].'"/></p>
<p>Email Address: <input type="text" name="email" size="20" maxlength="60" value="'.$rows[2].'"/></p>
<input type="submit" name="submit" value="Submit"/>
<input type="hidden" name="id" value="'.$id.'"/>
</form>';
}else{
echo '<p class="error">This page has been accessed in error.</p>';
}
mysqli_close($mysqli);
include('../include/footer.html');
?>從view_user3.php進入：
修改後提交：
給查詢結果標頁碼
1、view_users4.php
<?php #Script 10.4 -view_users.php
$page_title = 'View the Current Users';
include('../include/header.html');
echo '<h1>Registered Users</h1>';
require_once('../mysqli_connect.php');
$display = 10;
if(isset($_GET['p']) && is_numeric($_GET['p']))
{
$page = $_GET['p'];
}else{
$sql = "SELECT COUNT(user_id) FROM users"; //計算ID數目
$res = @mysqli_query($mysqli, $sql);
$row = @mysqli_fetch_array($res, MYSQLI_NUM);
$records = $row[0]; //獲取當前ID數目
//當前ID數目多餘每頁顯示的條數
if($records > $display)
{
//取不小於$records / $display的最小整數
$page = ceil($records / $display);
}else{
$page = 1;
}
}
//調取資料的起始位置
if(isset($_GET['s']) && is_numeric($_GET['s']))
{
$start = $_GET['s'];
}else{
$start = 0;
}
$sql = "SELECT last_name, first_name, DATE_FORMAT(registration_date, '%M %d, %Y') AS dr, user_id FROM users ORDER BY registration_date ASC LIMIT $start, $display";
$res = @mysqli_query($mysqli, $sql);
echo '<table border="1" cellspacing="0" cellpadding="10" align="center">
<tr>
<td align="left"><b>Edit</b></td>
<td align="left"><b>Delete</b></td>
<td align="left"><b>Last Name</b></td>
<td align="left"><b>First Name</b></td>
<td align="left"><b>Date Registered</b></td>
</tr>
';
$bg = '#eee';
while($rows = mysqli_fetch_array($res, MYSQLI_ASSOC))
{
$bg = ($bg == '#eee' ? '#fff' : '#eee');
echo '<tr bgcolor="'.$bg.'">
<td align = "letf"><a href="edit_user.php?id='.$rows['user_id'].'">Edit</a></td>
<td align = "letf"><a href="delete_user.php?id='.$rows['user_id'].'">Delete</a></td>
<td align="left">'.$rows['last_name'].'</td>
<td align="left">'.$rows['first_name'].'</td>
<td align="left">'.$rows['dr'].'</td>
</tr>';
}
echo '</table>';
mysqli_free_result($res);
mysqli_close($mysqli);
if($page > 1)
{
echo '<br/><p>';
$current_page = ($start / $display) + 1; //當前該顯示的頁數
if($current_page != 1) //當前顯示頁大於1
{
echo '<a href="view_users4.php?s='.($start - $display).'&p='.$page.'">Previous </a>';
}
for($i = 1; $i <= $page; $i++)
{
if($i != $current_page)
{
echo '<a href="view_users4.php?s='.(($display*($i-1))).'&p='.$page.'">'.$i.' </a>';
}else{
echo $i.' ';
}
}
if($current_page != $page)
{
echo '<a href="view_users4.php?s='.($start+$display).'&p='.$page.'"> Next</a>';
}
echo '</p>';
}//if_$page>1
include ('../include/footer.html');
?>
程式碼解析：
if($records > $display)
{
//取不小於$records / $display的最小整數
$page = ceil($records / $display);
}else{
$page = 1;
}——上述$page表示當前資料中的資料一共可以顯示成多少個頁面。
if($current_page != 1) //當前顯示頁大於1
{
echo '<a href="view_users4.php?s='.($start - $display).'&p='.$page.'">Previous </a>';
}——如果當前頁面不是第一個頁面（即頁碼>1），它還需要一個Previous連線，指向早期的結果集。前一頁的起點將是當前起點減去要顯示的數量。
for($i = 1; $i <= $page; $i++)
{
if($i != $current_page)
{
echo '<a href="view_users4.php?s='.(($display*($i-1))).'&p='.$page.'">'.$i.' </a>';
}else{
echo $i.' ';
}
}——通過1到頁面的總數的迴圈來建立一批連線，除了當前頁面外，其餘的頁面均會被連結
if($current_page != $page)
{
echo '<a href="view_users4.php?s='.($start+$display).'&p='.$page.'"> Next</a>';
}——如果當前頁面不是最終頁面，則存在一個Next連結到下頁面。
執行後如下：
建立可排序的顯示結果
1、view_users5.php
<?php #Script 10.4 -view_users.php
$page_title = 'View the Current Users';
include('../include/header.html');
echo '<h1>Registered Users</h1>';
require_once('../mysqli_connect.php');
$display = 10;
if(isset($_GET['p']) && is_numeric($_GET['p']))
{
$page = $_GET['p'];
}else{
$sql = "SELECT COUNT(user_id) FROM users"; //計算ID數目
$res = @mysqli_query($mysqli, $sql);
$row = @mysqli_fetch_array($res, MYSQLI_NUM);
$records = $row[0]; //獲取當前ID數目
//當前ID數目多餘每頁顯示的條數
if($records > $display)
{
//取不小於$records / $display的最小整數
$page = ceil($records / $display);
}else{
$page = 1;
}
}
//調取資料的起始位置
if(isset($_GET['s']) && is_numeric($_GET['s']))
{
$start = $_GET['s'];
}else{
$start = 0;
}
//設定查詢順序
$sort = (isset($_GET['sort'])) ? $_GET['sort'] : 'rd';
switch($sort)
{
case 'ln':
$order_by = 'last_name ASC';
break;
case 'fn':
$order_by = 'first_name DESC';
break;
case 'rd':
$order_by = 'registration_date DESC';
break;
default:
$order_by = 'registration_date ASC';
$sort = 'rd';
break;
}
$sql = "SELECT last_name, first_name, DATE_FORMAT(registration_date, '%M %d, %Y') AS dr, user_id FROM users ORDER BY $order_by LIMIT $start, $display";
/*$sql = "SELECT last_name, first_name, DATE_FORMAT(registration_date, '%M %d, %Y') AS dr, user_id FROM users ORDER BY registration_date ASC LIMIT $start, $display";*/
$res = @mysqli_query($mysqli, $sql);
echo '<table border="1" cellspacing="0" cellpadding="10" align="center">
<tr>
<td align="left"><b>Edit</b></td>
<td align="left"><b>Delete</b></td>
<td align="left"><b><a href="view_users5.php?sort=rn">Last Name</a></b></td>
<td align="left"><b><a href="view_users5.php?sort=fn">First Name</a></b></td>
<td align="left"><b><a href="view_users5.php?sort=rd">Date Registered</a></b></td>
</tr>
';
$bg = '#eee';
while($rows = mysqli_fetch_array($res, MYSQLI_ASSOC))
{
$bg = ($bg == '#eee' ? '#fff' : '#eee');
echo '<tr bgcolor="'.$bg.'">
<td align = "letf"><a href="edit_user.php?id='.$rows['user_id'].'">Edit</a></td>
<td align = "letf"><a href="delete_user.php?id='.$rows['user_id'].'">Delete</a></td>
<td align="left">'.$rows['last_name'].'</td>
<td align="left">'.$rows['first_name'].'</td>
<td align="left">'.$rows['dr'].'</td>
</tr>';
}
echo '</table>';
mysqli_free_result($res);
mysqli_close($mysqli);
if($page > 1)
{
echo '<br/><p>';
$current_page = ($start / $display) + 1; //當前該顯示的頁數
if($current_page != 1) //當前顯示頁大於1
{
/*echo '<a href="view_users4.php?s='.($start - $display).'&p='.$page.'&">Previous </a>';*/
echo '<a href="view_users5.php?s='.($start - $display).'&p='.$page.'&sort='.$sort.'">Previous </a>';
}
for($i = 1; $i <= $page; $i++)
{
if($i != $current_page)
{
echo '<a href="view_users5.php?s='.(($display*($i-1))).'&p='.$page.'&sort='.$sort.'">'.$i.' </a>';
}else{
echo $i.' ';
}
}
if($current_page != $page)
{
echo '<a href="view_users5.php?s='.($start+$display).'&p='.$page.'&sort='.$sort.'"> Next</a>';
}
echo '</p>';
}//if_$page>1
include ('../include/footer.html');
?>
<td align="left"><b><a href="view_users5.php?sort=rn">Last Name</a></b></td>
<td align="left"><b><a href="view_users5.php?sort=fn">First Name</a></b></td>
<td align="left"><b><a href="view_users5.php?sort=rd">Date Registered</a></b></td>——給標題新增排序連結，點選First Name執行如下：
