我无法在我的mysql数据库中向我的表添加数据

See php code below:

请参阅下面的PHP代码:

I have built the html form and the dropdown menu in the html form using <<<_END _END tags in php. also I added the following php code at the top of the htmlform that I had believed would allow me to enter a student name, student ID and select a course from the dropdown menu in the form. once those 3 values were entered in the form, the info should be added to the table enrolment in my mysql database. but i have had no luck figuring this out...

我已经使用php中的<<< _ END _END标签在html表单中构建了html表单和下拉菜单。我还在htmlform的顶部添加了以下php代码,我相信这些代码可以让我输入学生姓名,学生ID并从表格的下拉菜单中选择一个课程。一旦在表单中输入了这3个值,就应该将信息添加到我的mysql数据库中的表注册中。但我没有运气搞清楚......

//connect3.php--login information to my mysql database//

<?php
 define ('HOST', 'localhost');
 define ('USER', 'root');
 define ('PASS', '******');
?>


// html form and connection code//
    <?php
     include 'connect3.php';
     $link = mysql_connect (HOST, USER, PASS) or die(mysql_error());
     mysql_select_db ('milleruniversity', $link);

// Added mysql_real_escape() to protect against SQL-Injection
$code        = mysql_real_escape( $_POST['code'] ); 
$uid         = mysql_real_escape( $_POST['uid'] );
$studentname = mysql_real_escape( $_POST['studentname'] );

// Insert a row of information into the table "enrolment"

$query = "INSERT INTO enrolment (code, uid, studentname) VALUES('$code', '$uid', '$studentname')";
if(mysql_query($query)){
echo "inserted";}
else{
echo "fail";}
echo <<<_END
<table border='1'cellpadding="10">
<tr>
<td>
<h4>Miller University Registration Form</h4>
<p>Please Register as a new Student or current student for the following courses below.</p>
</td>
</tr>
<form action="draft5.php" method="post"><pre>
<tr>
<td>
  Student Name <input type="text" name="studentname" maxlength="30"/>
</td>
</tr>
<tr>
<td>
   Student ID <input type="text" name="uid" maxlength="11"/>
</tr>
</td>
<tr>
<td>
Select a course <select name="code" size="1">
<option value="DC-00040">Digital Communications</option>
<option value="VC-00030">Visual Culture</option>
<option value="WP-00080">World Politics</option>
</select>
</tr>
</td>
<tr>
<td>
        <input type="submit" value="Submit to Register" />
</tr>
</td>
</pre></form>
</table>
_END;

mysql_close($link);

?>

1 个解决方案

#1

It seems to me that you use this draft5.php page to display the form and to insert a row in your database. In that case the problem may come from the missing isset() around the $_POST data. (the first time you load the page the POST values are not set). You could use this code :

在我看来,您使用此draft5.php页面来显示表单并在数据库中插入一行。在这种情况下,问题可能来自$ _POST数据周围缺少的isset()。 (第一次加载页面时,未设置POST值)。你可以使用这段代码:

if( (isset($_POST['code']) AND (isset($_POST['uid']) AND (isset($_POST['studentname']){
//process the data base treatment and display an acknoledgment of the insert
// Check if these new code, uid and studentname respect the primary key constraint


}

else{
// Display your form
}

You could also consider using backticks ` around the names of your tables and colomns.

您还可以考虑在表和colomns的名称周围使用反引号。

If you want to prevent the same student to register twice in the same course you need to add primary keys in your tables. But this is not enough, indeed if you perform the insert request with a contraint violation on the primary key MySql will return an error. What you can do is check if the key exists prior to the insert request, if yes notify the user, if no perform the insert request.

如果您想阻止同一个学生在同一课程中注册两次,您需要在表格中添加主键。但这还不够,确实如果你在主键上执行带有约束违规的插入请求,MySql将返回错误。您可以做的是检查插入请求之前是否存在密钥,如果是,则通知用户,如果不执行插入请求。