[英]Query a MySQL Database then display retrieved text after form submit
從下拉菜單中進行選擇后,我試圖立即提交表單。 提交表單后,我想基於下拉菜單中的選擇向MySQL數據庫發送查詢,並顯示檢索到的文本。
目前,在下面的內容中,什么也沒有顯示,也沒有拋出任何錯誤。 JS提交事件處理程序可以工作,但是在頁面重新加載后,不會顯示新文本。
任何幫助是極大的贊賞。
提交表單的JS:
$(".platformSelectDropDown").change(function() {
$('.platformSelectForm').submit();
});
提交表單后運行的PHP:
if($_SERVER['REQUEST_METHOD'] == 'POST') {
$platform = $_POST['platformSelectDropDown'];
$description = call_data($tableName, $platform)['Description'];
$application = call_data($tableName, $platform)['Application'];
}
用於查詢和返回數據的PHP函數:
function call_data($tableName, $col, $platformName) {
include('connection.php');
$sql = 'SELECT * FROM $tableName WHERE platform_name = $platformName';
try {
return $db->query($sql);
}
catch (Exception $e) {
echo "Error! " . $e->getMessage() . "<br/>";
return array();
}
}
表格:
<form class="platformSelectForm" method="post" action="index.php">
<select name="platformSelectDropDown" class="platformSelectDropDown">
...
</select>
<ul class="indent">
<li><?php echo($description); ?></li>
<li><?php echo($application); ?></li>
</ul>
</form>
我相信下面的代碼將實現您想要的功能,並在安全性和功能上有所改進。 但是,請注意,從您的代碼來看,尚不清楚設置$tableName
位置,因此我只是將其硬編碼為我的測試表。 我將php和html混合在一起,因為它使我更容易解決問題,並且我認為它將使您更容易遵循我的解決方案。 如果您願意,沒有理由可以將其拆分回去並實現php部分的功能,類似於您的原始方法。 看看這個:
<html>
<body>
<form class="platformSelectForm" id="platformSelectForm" method="post">
<?php
// Get which dropdown option is selected, if any, so can keep selected on page reload
if(!isset($_POST['platformSelectDropDown'])) {
// Not postback, default to first option ("Select One")
$p0Select = ' selected';
$p1Select = '';
$p2Select = '';
} else {
// Is postback
// Set variables for query below
$tableName = 'tbl_platforms_1';
$platformName = $_POST['platformSelectDropDown'];
// set dropdown selection to whatever was select at form submission
if($platformName == 'Platform_1') {
$p1Select = ' selected';
} elseif ($platformName == 'Platform_2') {
$p2Select = ' selected';
} else {
$p0select = ' selected';
}
}
?>
<select name="platformSelectDropDown" class="platformSelectDropDown" onchange="document.getElementById('platformSelectForm').submit()">
<option value="Select_One"<?php echo $p0Select; ?>>Select One</option>
<option value="Platform_1"<?php echo $p1Select; ?>>Platform 1</option>
<option value="Platform_2"<?php echo $p2Select; ?>>Platform 2</option>
</select>
<?php
// If dropdown value is set and does not equal "Select_One"
if(isset($_POST['platformSelectDropDown'])&& $_POST['platformSelectDropDown'] != 'Select_One') {
?>
<ul class="indent">
<?php
try {
// Set database parameters
// Replace these values with appropriate values for your database
// (okay to use an include like you did originally)
$dbhost = 'your_database_host';
$dbname = 'your_database_name';
$dbuser = 'your_database_user';
$dbpass = 'your_database_user_password';
// Create PDO
$conn = new PDO("mysql:host=$dbhost;dbname=$dbname", $dbuser, $dbpass);
$conn->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
// Prepare SQL statement and bind parameters
$stmt = $conn->prepare("SELECT * FROM $tableName WHERE platform_name = :platformName");
$stmt->bindValue(':platformName', $platformName, PDO::PARAM_STR);
// Execute statement and return results in an associative array (e.g., field_name -> value)
$stmt->execute();
$results = $stmt->fetchAll(PDO::FETCH_ASSOC);
// Close Connection
$conn = null;
// For each row that was returned, output results
for ($i = 0; $i < count($results); $i++) {
echo '<li>' .$results[$i]['Description'] .'</li>';
echo '<li>' .$results[$i]['Application'] .'</li>';
}
} catch (Exception $e) {
echo '<li>Error! ' .$e->getMessage() . '</li>';
}
?>
</ul>
<?php
};
?>
</form>
</body>
</html>
我用來設置測試的代碼:
DROP TABLE IF EXISTS tbl_platforms_1;
CREATE TABLE IF NOT EXISTS tbl_platforms_1 (
id int AUTO_INCREMENT NOT NULL,
platform_name varchar(20),
Description varchar(20),
Application varchar(20),
PRIMARY KEY (id)
);
INSERT INTO
tbl_platforms_1
(platform_name, Description, Application)
VALUES
('Platform_1', 'Description 1', 'Application 1'),
('Platform_2', 'Description 2', 'Application 2');
如果這解決了您的問題,請記住標記為已回答,這樣每個人都將知道您不再需要幫助(因此,我花在提出此解決方案上的一小時便會得到回報:-)。 如果這樣做不能解決您的問題,請提供盡可能多的詳細信息,說明當前結果與您期望的結果有何不同,我將嘗試對其進行修改以滿足您的需求。 謝謝!
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