Replacing PHP "undefined variable" error? - php

Question

so basically I want to make an online dictionary, the word to be searched for is introduced by an input, and I want to make so that if it can't find the word+definition in db to say a message like "We couldn't find any definition" or something like that, in my code because it can't find it , it ways "undefined variable"
<?php
include ("header.php");
$search = $_POST['se'];
include ("connect.php");
$dictionary=mysqli_query($con,"SELECT * FROM `dictionary` WHERE word = '$search'");
while($row = mysqli_fetch_array( $dictionary )) {
$word=$row['word'];
$description=$row['definition'];
}
echo "<div class=\"webResult\">
<h2>$word</h2>
<p>$description</p>
</div>";
include ("footer.php");
?>
P.S.: I know my code is vulnerable to SQLi , but I'll fix that later.

Answer 1

try wrapping the undefined vars in isset
if (isset($word) && isset($description)) {
echo "<div class=\"webResult\">
<h2>$word</h2>
<p>$description</p>
</div>";
}
else {
echo "Nothing found";
}
Same goes for $search = $_POST['se'];
if(!isset($_POST['se'])) {
echo "Nothing found";
exit;
}

Answer 2

if($row = mysqli_fetch_array( $dictionary )) {
$word=$row['word'];
$description=$row['definition'];
echo "<div class=\"webResult\">
<h2>$word</h2>
<p>$description</p>
</div>";
} else {
echo "$search not found";
}

Answer 3

while($row = mysqli_fetch_array( $dictionary )) {
$word=$row['word'];
$description=$row['definition'];
}
if(!empty($word) && !empty($description)){
echo '<div class=\"webResult\">';
echo '<h2>$word</h2>';
echo '<p>$description</p>';
echo '</div>";
}else{
echo 'could not find your word';
}
include ("footer.php");
?>
You have to validate your variables if its have value or not

Answer 4

The variables $word and $description are first created inside the while loop. This means that they do not have any scope outside it. This should be the most probable cause, since you are getting a variable not defined error.
There are a couple of options here.
One, you could create these variables outside the while loop, and then assign them new values as you are doing now. Here is what your code might look like, if you choose to do it this way:
$search = $con->escape_string($_POST['se']);
$dictionary = $con->query("SELECT * FROM `dictionary` WHERE word = '$search'");
$word = "";
$description = "";
while($row = $dictionary->fetch_assoc())
{
$word = $row['word'];
$description = $row['definition'];
}
if (!empty($word) && !empty($description))
{
echo '<div class="webResult"><h2>' . $word . '</h2><p>' . $description . '</p></div>';
}
else
{
echo "We couldn't find any definition";
}
This will work for you if you have multiple results in the returned mysqli_resource, and want to use the last in the list.
Two, if you are likely to get only one result returned, or if you just want to use the first result in the list, you can have the echo statement inside an if statement that checks if a valid result is returned. For example:
$search = $con->escape_string($_POST['se']);
$dictionary = $con->query("SELECT * FROM `dictionary` WHERE word = '$search'");
$word = "";
$description = "";
$row = $dictionary->fetch_assoc();
if($row)
{
$word = $row['word'];
$description = $row['definition'];
if (!empty($word) && !empty($description))
{
echo '<div class="webResult"><h2>' . $word . '</h2><p>' . $description . '</p></div>';
}
else
{
echo "We couldn't find any definition";
}
}
Note:
In the above examples, we use !empty() to check the variables. This is because isset() is pointless here, since we have already created (set) the variables ourselves.
Things to read up:
Scope of variables - http://php.net/manual/en/language.variables.scope.php
empty() function - http://php.net/manual/en/function.empty.php
Object oriented mysqli - http://php.net/manual/en/mysqli.quickstart.dual-interface.php

Answer 5

Try this:
include ("header.php");
$search = $_POST['se'];
include ("connect.php");
$dictionary=mysqli_query($con,"SELECT * FROM `dictionary` WHERE word = '$search'");
while($row = mysqli_fetch_array( $dictionary )) {
$word=$row['word'];
$description=$row['definition'];
}
if(isset($word)){
echo "<div class=\"webResult\">
<h2>$word</h2>
<p>$description</p>
</div>";
}
else{
echo "We couldn't find any definition";
}
include ("footer.php");