Update mysql database and skip empty fields - php

Question

I have two pages, edit.php and editdone.php.
On the edit.php I am able to fill information, which is being sent to editdone.php. That page is then running a query that updates data in the mysql database.
The problem is; if I leave an input field on edit.php empty, editdone.php will then replace the current information in the database with empty data(nothing).
What I want to do is to make the editdone.php update data if something was written in the fields of edit.php. So if I choose to leave some fields empty and for example only fill one field in the form, I want to only update the filled fields with the filled data and NOT replace the not filled field with empty data. Those field should then, if I haven't filled any data in edit.php, keep the already existing data.
edit.php
<?php
if (!empty($error_msg)) {
echo $error_msg;
}
$cn = $_POST['cname'];
?>
<form action="editdone.php" method="POST" enctype="multipart/form-data" name="editdone" onsubmit="return validateForm()">
<input type="hidden" name="namec" value="<?php echo htmlspecialchars($cn); ?>">
<br>
Fyll i Företagets namn: <br>
<input type="text" name="company_name" id="company_name">
<br><br>
Lägg till en logga:
<input type="file" name="image" id="image">
<br><br>
Description:<br>
<textarea name="description" id="description" rows="4" cols="50"></textarea>
<br>
<br>
Fyll i välkomnings meddelande:<br>
<textarea name="welcome_text" id="welcome_text" rows="5" cols="50"></textarea>
<br>
<br>
Fyll i ett tack meddelande:<br>
<textarea name="thanks_message" id="thanks_message" rows="5" cols="50"></textarea>
<br>
<br>
<input type="submit" name="submit" value="Nästa" />
</form>
editdone.php
<?php
ini_set('display_errors',1);
error_reporting(E_ALL);
if(mysqli_connect_errno())
{
echo mysqli_connect_error();
}
$namenamec = $_POST['namec'];
$company_name = $_POST['company_name'];
$description = $_POST['description'];
$welcome_text = $_POST['welcome_text'];
$thanks_message = $_POST['thanks_message'];
$image = addslashes (file_get_contents($_FILES['image']['tmp_name']));
$logo = getimagesize($_FILES['image']['tmp_name']);
$image_type = $logo['mime'];
$q = "UPDATE project SET project_name='$company_name', description='$description', image='$image', image_type='$image_type', welcome_text='$welcome_text', thanks_message='$thanks_message' WHERE project_name='$namenamec' ";
$r = mysqli_query($mysqli,$q);
if($r)
{
echo "<br>Information stored successfully";
}
?>

Answer 1

For every input/textarea in edit.php, insert a <input type="hidden" value="company_name_old> etc... with the previous value. Then in editdone.php, check if the value in POST is empty or not.
<?php
$company_name = $_POST['company_name'];
if($company_name==""){
$company_name=$_POST['company_name_old'];
}
...
?>

Answer 2

1 cheap "hack" is to assign the current value of the field to the value of the input field and then concat the two strings or values together then save that var. to the database.

Answer 3

<?php
ini_set('display_errors',1);
error_reporting(E_ALL);
if(mysqli_connect_errno())
{
echo mysqli_connect_error();
}
$company_name = "";
$description = "";
$welcome_text = "";
$thanks_message = "";
$image = "";
$logo = "";
$image_type = "";
$namenamec = $_POST['namec'];
$company_name = $_POST['company_name'];
$description = $_POST['description'];
$welcome_text = $_POST['welcome_text'];
$thanks_message = $_POST['thanks_message'];
if( isset($_FILES) )
{
if( !empty($_FILES) )
{
if( isset($_FILES['image']['tmp_name']) )
{
if( $_FILES['image']['tmp_name'] != "" && !empty($_FILES['image']['tmp_name']) )
{
$image = addslashes (file_get_contents($_FILES['image']['tmp_name']));
if( $image != "" && !empty($image) )
{
$logo = getimagesize($_FILES['image']['tmp_name']);
$image_type = $logo['mime'];
}
}
}
}
}
$update_values = array();
if($company_name != "")
$update_values[] = "project_name='".$company_name."'";
if($description != "")
$update_values[] = "description='".$description."'";
if($image != "")
$update_values[] = "image='".$image."'";
if($image_type != "")
$update_values[] = "image_type='".$image_type."'";
if($welcome_text != "")
$update_values[] = "welcome_text='".$welcome_text."'";
if($thanks_message != "")
$update_values[] = "thanks_message='".$thanks_message."'";
$update_values_imploded = implode(', ', $update_values);
if( !empty($update_values) )
{
$q = "UPDATE project SET $update_values_imploded WHERE project_name='$namenamec' ";
$r = mysqli_query($mysqli,$q);
if($r)
{
echo "<br>Information stored successfully";
}
}
?>

Answer 4

Try replacing your query like this.
$q = "UPDATE project SET ";
$q .= $company_name ? "project_name='$company_name', " : "";
$q .= $description ? "description='$description', " : "";
$q .= $image ? "image='$image'," : "";
... so on(all fields)
$q .= "WHERE project_name='$namenamec'";
Make sure you remove , for last value

Answer 5

you can do like this here i have made only one variable you can check for each posted variable and append the $q variable as on
$q = "UPDATE project SET";
if(isset($_POST['namec']) && $_POST['namec']!=""){
$q.=" project_name='".$_POST['namec']."' ,";
}
$q=rtrim(',',$q);
$q.="WHERE project_name=".$namenamec;