How to delete a saved row in mysql database after clicking on a 'exit' button

Question

I currently have an upload button that saves all types of files to a mysql table. I have an exit button that I want to delete the currently uploaded files if clicked. NOTE: all files uploaded on current page has same referenceID so the query is as easy as saying delete all from table where id=id..

Here is the button:

<button type="submit" name="submit" value="exit" style="float:left;
   class="buttonLW" href="https://BACK-LINK">exit
</button>

Here is the php delete query (suedo code):

if ($submitButton === "delete-new") { 

    $query15 ="DELETE * FROM table WHERE id='{$id}'";

}

my question, is the button aloud to use this sort of format? am I allowed to say if ($submitButton === "delete-new") without using a form?

How can I go about deleting the currently saved files with same id after clicking my exit button.

Answer 1

Upfront, the style value isn't terminated, you're missing the closing quote " .

If you get $submitButton with

$submitButton = $_POST['submit'];

you can compare it that way, but the value will be exit and not delete-new . So you must rather say

if ($submitButton === 'exit') {
    // ...
}

or change value="exit" to value="delete-new" .

Which leads to the next point, the delete statement. The delete statement must look like

delete from mytable WHERE id = '$id'

But don't do it this way, because this is unsafe and invites all sorts of SQL injection. Better use prepared statments , eg

delete from mytable WHERE id = ?

and bind $id when you execute the prepared statement.