Add, Edit, Delete with data table using PDO in PHP/MySQL

CREATE TABLE IF NOT EXISTS `student` (
  `student_id` INT(100) NOT NULL AUTO_INCREMENT,
  `fname` VARCHAR(100) NOT NULL,
  `mname` VARCHAR(100) NOT NULL,
  `lname` VARCHAR(100) NOT NULL,
  `address` VARCHAR(100) NOT NULL,
  `email` VARCHAR(100) NOT NULL,
  PRIMARY KEY (`student_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ;

<?php $conn = new PDO('mysql:host=localhost; dbname=add_pdo','root', ''); ?>

					<form method="post" action="add.php"  enctype="multipart/form-data">
					<table class="table1">
						<tr>
							<td><label style="color:#3a87ad; font-size:18px;">FirstName</label></td>
							<td width="30"></td>
							<td><input type="text" name="fname" placeholder="FirstName" required /></td>
						</tr>
						<tr>
							<td><label style="color:#3a87ad; font-size:18px;">MiddleName</label></td>
							<td width="30"></td>
							<td><input type="text" name="mname" placeholder="MiddleName" required /></td>
						</tr>
						<tr>
							<td><label style="color:#3a87ad; font-size:18px;">LastName</label></td>
							<td width="30"></td>
							<td><input type="text" name="lname" placeholder="LastName" required /></td>
						</tr>
						<tr>
							<td><label style="color:#3a87ad; font-size:18px;">Address</label></td>
							<td width="30"></td>
							<td><input type="text" name="address" placeholder="Address" required /></td>
						</tr>
						<tr>
							<td><label style="color:#3a87ad; font-size:18px;">Email</label></td>
							<td width="30"></td>
							<td><input type="email" name="email" placeholder="Email" required /></td>
						</tr>
 
					</table>
 
 
    </div>
    <div class="modal-footer">
    <button class="btn" data-dismiss="modal" aria-hidden="true">Close</button>
<button type="submit" name="Submit" class="btn btn-primary">Add</button>
    </div>
 
 
					</form>

<?php
require_once('db.php');
 
$fname= $_POST['fname'];
$mname= $_POST['mname'];
$lname= $_POST['lname'];
$address= $_POST['address'];
$email= $_POST['email'];
 
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "INSERT INTO student (fname, mname, lname, address, email)
VALUES ('$fname', '$mname', '$lname', '$address', '$email')";
 
$conn->exec($sql);
echo "<script>alert('Account successfully added!'); window.location='index.php'</script>";
?>

<?php
include('db.php');
$result = $conn->prepare("SELECT * FROM student where student_id='$ID'");
$result->execute();
for($i=0; $row = $result->fetch(); $i++){
$id=$row['student_id'];
?>
<form class="form-horizontal" method="post" action="edit_PDO.php<?php echo '?student_id='.$id; ?>"  enctype="multipart/form-data" style="float: right;">
                                <legend><h4>Edit</h4></legend>
                                <h4>Personal Information</h4>
                                <hr>
								<div class="control-group">
                                    <label class="control-label" for="inputPassword">FirstName:</label>
                                    <div class="controls">
                                        <input type="text" name="fname" required value=<?php echo $row['fname']; ?>>
                                    </div>
                                </div>
								<div class="control-group">
                                    <label class="control-label" for="inputPassword">MiddleName:</label>
                                    <div class="controls">
                                        <input type="text" name="mname" required value=<?php echo $row['mname']; ?>>
                                    </div>
                                </div>
                                <div class="control-group">
                                    <label class="control-label" for="inputEmail">LastName:</label>
                                    <div class="controls">
                                        <input type="text" name="lname" required value=<?php echo $row['lname']; ?>>
                                    </div>
                                </div>
                                <div class="control-group">
                                    <label class="control-label" for="inputPassword">Address:</label>
                                    <div class="controls">
                                        <input type="text" name="address" required value=<?php echo $row['address']; ?>>
                                    </div>
                                </div>
                                <div class="control-group">
                                    <label class="control-label" for="inputPassword">Email:</label>
                                    <div class="controls">
                                        <input type="email" name="email" required value=<?php echo $row['email']; ?>>
                                    </div>
                                </div>
 
								 <div class="control-group">
                                    <div class="controls">
 
                                        <button type="submit" name="update" class="btn btn-success" style="margin-right: 65px;">Save</button>
										<a href="index.php" class="btn">Back</a>
                                    </div>
                                </div>
                            </form>
<?php } ?>

<?php
include 'db.php';
 
$get_id=$_REQUEST['student_id'];
 
$fname= $_POST['fname'];
$mname= $_POST['mname'];
$lname= $_POST['lname'];
$address= $_POST['address'];
$email= $_POST['email'];
 
$sql = "UPDATE student SET fname ='$fname', mname ='$mname', lname ='$lname', 
address ='$address', email ='$email' WHERE student_id = '$get_id' ";
 
$conn->exec($sql);
echo "<script>alert('Successfully Edit The Account!'); window.location='index.php'</script>";
?>

<div id="delete<?php  echo $id;?>" class="modal hide fade" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
<div class="modal-header">
<h3 id="myModalLabel">Delete</h3>
</div>
<div class="modal-body">
<p><div style="font-size:larger;" class="alert alert-danger">Are you Sure you want Delete <b style="color:red;"><?php echo $row['fname']." ".$row['mname']." ".$row['lname'] ; ?></b> Data?</p>
</div>
<hr>
<div class="modal-footer">
<button class="btn btn-inverse" data-dismiss="modal" aria-hidden="true">No</button>
<a href="delete.php<?php echo '?student_id='.$id; ?>" class="btn btn-danger">Yes</a>
</div>
</div>
</div>

<?php
require_once('db.php');
 
$get_id=$_GET['student_id'];
 
// sql to delete a record
$sql = "Delete from student where student_id = '$get_id'";
 
// use exec() because no results are returned
$conn->exec($sql);
header('location:index.php');
?>