将表单连接到数据库错误

Question

Hello I am trying to connect a page to a MySQL database for newsletter signup. I have the database with 3 fields, id, name, email. The database is named newsletter and the table is named newsletter. Everything seems to be fine but I am getting this error

Notice: Undefined index: Name in C:\wamp\www\insert.php on line 12 Notice: Undefined index: Name in C:\wamp\www\insert.php on line 13

Here is my form code.

<form action="insert.php" method="post">
<input type="text" value="Name" name="Name" id="Name" class="txtfield" onblur="javascript:if(this.value==''){this.value=this.defaultValue;}" onfocus="javascript:if(this.value==this.defaultValue){this.value='';}" />
<input type="text" value="Enter Email Address"  name="Email" id="Email" class="txtfield" onblur="javascript:if(this.value==''){this.value=this.defaultValue;}" onfocus="javascript:if(this.value==this.defaultValue){this.value='';}" />
<input type="submit" value="" class="button" />
</form>

Here is my insert.php file.

<?php
$host="localhost"; // Host name 
$username="root"; // Mysql username 
$password=""; // Mysql password 
$db_name="newsletter"; // Database name 
$tbl_name="newsletter"; // Table name
// Connect to server and select database.
 mysql_connect("$host", "$username", "$password")or die("cannot connect"); 
 mysql_select_db("$db_name")or die("cannot select DB");

// Get values from form 
$name=$_POST['Name'];
$email=$_POST['Email'];

// Insert data into mysql 
$sql="INSERT INTO $tbl_name(name, email)VALUES('$name', '$email')";
$result=mysql_query($sql);

// if successfully insert data into database, displays message "Successful". 
if($result){
echo "Successful";
echo "<BR>";
echo "<a href='index.html'>Back to main page</a>";
}

else {
 echo "ERROR";
 }
?> 

 <?php 
// close connection 
mysql_close();
?>

Answer 1

The error indicates the index Name is not found in the $_POST[] array. It is a PHP notice, and not a show-stopping error, but rather is intended to communicate that you are referencing a value which does not exist. If it is normal/expected that this value might be empty/null then the notice can be safely ignored.

Beyond this problem, you should be sanitizing public values prior to referencing within the SQL statement, ie:

$name = mysql_real_escape_string($_POST['Name']);
$email = mysql_real_escape_string($_POST['Email']);

A few other notes:

• In the call to mysql_connect() it is not necessary to wrap variables $host, $username or $password in quotes. The same is true with $db_name in call to mysql_select_db(). They are already strings as defined in the lines above and so this is excessive.

• Perhaps some validation on the values in $_POST[] would be a good idea prior to SQL query? This way you can output an error if, for example, the Name value is empty.