下面我有一个模块下拉菜单，它从数据库中获取模块列表，并且显然将它们显示在下拉菜单中。它还在$output变量中显示所选模块编号和模块名称，并在隐藏输入 ( $hiddenoutput) 中显示所选模块的模块 ID（当文本输入在更改为隐藏之前为文本时，这已成功发送文本）
$active = 1;
$sql = "SELECT ModuleId, ModuleNo, ModuleName FROM Module WHERE ModuleActive = ? ORDER BY ModuleNo";
$sqlstmt=$mysqli->prepare($sql);
$sqlstmt->bind_param("i",$active);
$sqlstmt->execute();
$sqlstmt->bind_result($dbModuleId, $dbModuleNo, $dbModuleName);
$modules = array(); // easier if you don't use generic names for data
$output = "";
$hiddenoutput = "";
$moduleHTML = "";
$moduleHTML .= '<select name="module" id="modulesDrop">'.PHP_EOL;
$moduleHTML .= '<option value="">Please Select</option>'.PHP_EOL;
while($sqlstmt->fetch())
{
$moduleno = $dbModuleNo;
$module = $dbModuleId;
$modulename = $dbModuleName;
$moduleHTML .= "<option value='".$module."'>" . $moduleno . " - " . $modulename . "</option>".PHP_EOL;
if (isset($_POST['module']) && ($_POST['module'] == $module)) {
$output .= "<p><strong>Selected Module:</strong> " . $moduleno . " - " . $modulename . "</p>";
$hiddenoutput .= "<p><input type='hidden' id='hiddenoutput' name='hiddenmodule' value='". $module ."'></p>";
}
}
$moduleHTML .= '</select>';
$submittedModuleId = (isset($_POST['module'])) ? $_POST['module'] : '';
$output = (isset($output)) ? $output : '';
$hiddenoutput = (isset($hiddenoutput)) ? $hiddenoutput : '';
详细信息显示在以下表格中：
<form action="<?php echo htmlentities($_SERVER['PHP_SELF']); ?>" method="post">
<table>
<tr>
<th>Module: <?php echo $moduleHTML; ?><input id="moduleSubmit" type="submit" value="Submit" name="submit" /></th>
</tr>
<tr>
<td><span id="errormsg"><?php echo $errormsg; ?></span><?php echo $hiddenoutput . $output; ?></td>
</tr>
</table>
</form>
但我真正不明白的是，在我下面的 INSERT sql 中，它能够检索和插入除一个之外的所有值，即隐藏输入中显示的 Module Id 的值。它一直在说：
Warning: mysqli_stmt::execute(): (23000/1048): Column 'ModuleId' cannot be null in ... on line 172
我的问题是为什么它不能检索并在数据库中插入模块 ID 的值？下面是代码：
session_start();
if (isset($_POST['hiddenmodule'])) {
$_SESSION['hiddenmodule'] = $_POST['hiddenmodule'];
}
if (isset($_POST['id'])) {
$_SESSION['id'] = $_POST['id'];
}
if(isset($_POST['sessionNum'])){
//Declare my counter for the first time
$_SESSION['initial_count'] = $_POST['sessionNum'];
$_SESSION['sessionNum'] = $_POST['sessionNum'];
}
if (!isset($_SESSION['sessionCount'])) {
$_SESSION['sessionCount'] = 1;
}
else if ($_SESSION['sessionCount'] < $_SESSION['sessionNum']) {
++$_SESSION['sessionCount'];
}
$sessionMinus = $_SESSION['sessionCount'];
if (isset($_POST['durationChosen'])) {
$_SESSION['durationChosen'] = $_POST['durationChosen'];
}
if (isset($_POST['dateChosen'])) {
$_SESSION['dateChosen'] = $_POST['dateChosen'];
}
if (isset($_POST['timeChosen'])) {
$_SESSION['timeChosen'] = $_POST['timeChosen'];
}
if (isset($_POST['textQuestion'])) {
$_SESSION['textQuestion'] = $_POST['textQuestion'];
}
if (isset($_POST['textMarks'])) {
$_SESSION['textMarks'] = $_POST['textMarks'];
}
if (isset($_POST['totalWeight'])) {
$_SESSION['totalWeight'] = $_POST['totalWeight'];
}
if (isset($_POST['buildings'])) {
$_SESSION['buildings'] = $_POST['buildings'];
}
if (isset($_POST['rooms'])) {
$_SESSION['rooms'] = $_POST['rooms'];
}
if (isset($_POST['teacherforename'])) {
$_SESSION['teacherforename'] = $_POST['teacherforename'];
}
if (isset($_POST['teachersurname'])) {
$_SESSION['teachersurname'] = $_POST['teachersurname'];
}
if (isset($_POST['teacherusername'])) {
$_SESSION['teacherusername'] = $_POST['teacherusername'];
}
var_dump($_POST);
var_dump($_SESSION);
// connect to the database
include('connect.php');
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
die();
}
$sql = "
SELECT TeacherId
FROM Teacher
WHERE TeacherUsername = ?
";
if (!$stmt = $mysqli->prepare($sql)) {
// Handle errors with prepare operation here
}
// Bind parameter for statement
$stmt->bind_param("s", $_SESSION['teacherusername']);
// Execute the statement
$stmt->execute();
// This is what matters. With MySQLi you have to bind result fields to
// variables before calling fetch()
$stmt->bind_result($teacherid);
// This populates $teacherid
$stmt->fetch();
// Close the statment
$stmt->close();
if($_SERVER['REQUEST_METHOD'] == 'POST')
{
$time = str_replace(array(' Hrs ', ' Mins ', ' Secs'), array(':', ':', ''), $_SESSION['durationChosen']);
for ($i = 1, $n = $_SESSION['sessionNum']; $i <= $n; $i++) {
$insertsql = "
INSERT INTO Session
(SessionName, SessionTime, SessionDate, SessionWeight, SessionDuration, TotalMarks, ModuleId, TeacherId, Room)
VALUES
(?, ?, ?, ?, ?, ?, ?, ?, ?)
";
if (!$insert = $mysqli->prepare($insertsql)) {
// Handle errors with prepare operation here
}
$sessname = $_SESSION['id'] . ($n == 1 ? '' : $i);
$sessdate = date("Y-m-d", strtotime($_SESSION['dateChosen']));
$insert->bind_param("sssisiiis", $sessname, $_SESSION['timeChosen'], $sessdate,
$_SESSION['totalWeight'], $time, $_SESSION['textMarks'],
$_SESSION['hiddenmodule'], $teacherid, $_SESSION['rooms']);
$insert->execute();
if ($insert->errno) {
// Handle query error here
}
$insert->close();
}
}
以下是var_dump($_SESSION)输出：
array(17) {
["teacherid"]=> int(49)
["teacherusername"]=> string(8) "u0867587"
["teacherforename"]=> string(5) "Bruce"
["teachersurname"]=> string(5) "Finch"
["id"]=> string(5) "XNTLR"
["initial_count"]=> string(1) "1"
["sessionNum"]=> string(1) "1"
["sessionCount"]=> int(1)
["durationChosen"]=> string(22) "02 Hrs 00 Mins 00 Secs"
["dateChosen"]=> string(10) "15-12-2012"
["timeChosen"]=> string(5) "10:00"
["textQuestion"]=> string(1) "1"
["textMarks"]=> string(1) "5"
["totalWeight"]=> string(1) "0"
["buildings"]=> string(14) "Canalside East"
["rooms"]=> string(7) "CE01/04"
["hiddenmodule"]=> NULL }