Q:

PHP MySQL data insertion in database no error is showing

No error is showing and also code is not working.  Nothing happens to database too.   When I open my page insert.php and fill out the details it just reset the form. 
//insert.php
<html>
    <head>
        <title>Insert Record</title>
    </head>
    <body>
        <form action="insert.php" method="post">
        Name: <input type="text" name="name"><br><p />
        Roll No.:  <input type="text" name="rollno"><br><p />
        Duration: <input type="text" name="duration"><br><p />
        Course: <input type="text" name="course"><br><p />
        Date of Birth: <input type="text" name="dob"><br><p />
        Photo: <input type="file" name="image"><br><p />
        <input type="submit" name="submit" value="Submit">
    </form>

    <? php
    error_reporting(0);

    //connection
    $servername = "localhost";
    $username = "root";
    $password = "";
    $dbname = "vision";

    // Create connection
    $conn = new mysqli($servername, $username, $password,$dbname);

    // Check connection
    if ($conn->connect_error) {
        die("Connection failed: " .  $conn->connect_error);
    } 

    $file = $_FILES["image"]["tmp_name"];
     if (! isset($file))
         {echo "Please Select an Image";}
        else
        { 
            $name = $_POST["name"];
            $rollno = $_POST["rollno"];
            $duration = $_POST["duration"];
            $dob = $_POST["dob"];
            $course = $_POST["course"];
            $image=addslashes(file_get_contents($_FILES["image"]["tmp_name"]));
            //$image_name= addslashes($_FILES["image"]["name"]);
            $image_size=  getimagesize($_FILES["image"]["tmp_name"]);

    //inserting data

            if($image_size==FALSE)
                {echo "That's not an Image";}
            else
            {       
                $sql = mysqli_query($conn,"INSERT INTO record(rollno,name,duration,dob,course,image)VALUES('$rollno','$name','$duration','$dob','$course','$image')");

                if($conn->query($sql) == TRUE)
                {
                    echo "<br>Input data is succeed";
                } 
                else
                {
                    echo "<br>Input data is fail";
                }
            }
        }
    ? >
    </body>
    </html>

A:

That's because nothing will be displayed when no image exists and there never will be an image.  When you want to POST an image you need to add the enctype tag multipart/form-data.  
Change 
<form action="insert.php" method="post">

To
<form action="test.php" enctype="multipart/form-data" method="post">

And if you add an image to your form it will reach the $sql = mysqli_query($conn,"INS.... line.