update image if uploaded else use previosly stored image - php

Question

<?php
include '../db_conx.php';
$id = $_POST['id'];
$file = addslashes(file_get_contents($_FILES["college_image"]["tmp_name"]));
$insert_data1 = mysqli_real_escape_string($db_conx,$_POST['college_overview']);
$insert_data2 = mysqli_real_escape_string($db_conx,$_POST['college_courses']);
$insert_data3 = mysqli_real_escape_string($db_conx,$_POST['college_facilities']);
$test = "UPDATE college_details SET college_overview='$insert_data1', college_courses='$insert_data2', college_facilities='$insert_data3',college_image = '$file' where id = '$id' ";
if (mysqli_query($db_conx,$test)){
header("Location:college.php?success");
}
{
echo("Error description: " . mysqli_error($db_conx));
}
?>
Whenever i try to update without uploading a new image the previously stored image gets removed. How do i keep the old image when no file is uploaded

Answer 1

You can check whether the upload file is empty or not using simple if else statement and reformat your sql statement accordingly:
if(!file_exists($_FILES["college_image"]["tmp_name"]) ||
!is_uploaded_file($_FILES["college_image"]["tmp_name"])) {
$test = "UPDATE college_details SET college_overview='$insert_data1',
college_courses='$insert_data2', college_facilities='$insert_data3',
where id = $id ";
//No file is uploaded, we skip updating the image.
}else{
//Upload File is there, we update the image file in the database
$test = "UPDATE college_details SET college_overview='$insert_data1',
college_courses='$insert_data2', college_facilities='$insert_data3',
college_image = '$file' where id = $id ";
}
Your code is vulnerable to sql injection. Use prepared statement to update your data.