update.php

    <?php

    // Include config file

    require_once 'config.php';

     

    // Define variables and initialize with empty values

    $name = $address = $salary = "";

    $name_err = $address_err = $salary_err = "";

     

    // Processing form data when form is submitted

    if(isset($_POST["id"]) && !empty($_POST["id"])){

        // Get hidden input value

        $id = $_POST["id"];

        

        // Validate name

        $input_name = trim($_POST["name"]);

        if(empty($input_name)){

            $name_err = "Please enter a name.";

        } elseif(!filter_var(trim($_POST["name"]), FILTER_VALIDATE_REGEXP, array("options"=>array("regexp"=>"/^[a-zA-Z'-.\s ]+$/")))){

            $name_err = 'Please enter a valid name.';

        } else{

            $name = $input_name;

        }

        

        // Validate address address

        $input_address = trim($_POST["address"]);

        if(empty($input_address)){

            $address_err = 'Please enter an address.';     

        } else{

            $address = $input_address;

        }

        

        // Validate salary

        $input_salary = trim($_POST["salary"]);

        if(empty($input_salary)){

            $salary_err = "Please enter the salary amount.";     

        } elseif(!ctype_digit($input_salary)){

            $salary_err = 'Please enter a positive integer value.';

        } else{

            $salary = $input_salary;

        }

        

        // Check input errors before inserting in database

        if(empty($name_err) && empty($address_err) && empty($salary_err)){

            // Prepare an update statement

            $sql = "UPDATE media SET name=?, title=?, size=? WHERE id=?";

             

            if($stmt = mysqli_prepare($link, $sql)){

                // Bind variables to the prepared statement as parameters

                mysqli_stmt_bind_param($stmt, "sssi", $param_name, $param_address, $param_salary, $param_id);

                

                // Set parameters

                $param_name = $name;

                $param_address = $address;

                $param_salary = $salary;

                $param_id = $id;

                

                // Attempt to execute the prepared statement

                if(mysqli_stmt_execute($stmt)){

                    // Records updated successfully. Redirect to landing page

                    header("location: index.php");

                    exit();

                } else{

                    echo "Something went wrong. Please try again later.";

                }

            }

             

            // Close statement

            mysqli_stmt_close($stmt);

        }

        

        // Close connection

        mysqli_close($link);

    } else{

        // Check existence of id parameter before processing further

        if(isset($_GET["id"]) && !empty(trim($_GET["id"]))){

            // Get URL parameter

            $id =  trim($_GET["id"]);

            

            // Prepare a select statement

            $sql = "SELECT * FROM media WHERE id = $id";

            if($stmt = mysqli_prepare($link, $sql)){

                // Bind variables to the prepared statement as parameters

                mysqli_stmt_bind_param($stmt, "i", $param_id);

                

                // Set parameters

                $param_id = $id;

                

                // Attempt to execute the prepared statement

                if(mysqli_stmt_execute($stmt)){

                    $result = mysqli_stmt_get_result($stmt);

        

                    if(mysqli_num_rows($result) == 1){

                        /* Fetch result row as an associative array. Since the result set contains only one row, we don't need to use while loop */

                        $row = mysqli_fetch_array($result, MYSQLI_ASSOC);

                        

                        // Retrieve individual field value

                        $name = $row["name"];

                        $address = $row["title"];

                        $salary = $row["size"];

                    } else{

                        // URL doesn't contain valid id. Redirect to error page

                        header("location: error.php");

                        exit();

                    }

                    

                } else{

                    echo "Oops! Something went wrong. Please try again later.";

                }

            }

            

            // Close statement

            mysqli_stmt_close($stmt);

            

            // Close connection

            mysqli_close($link);

        }  else{

            // URL doesn't contain id parameter. Redirect to error page

            header("location: error.php");

            exit();

        }

    }

    ?>

     

    <!DOCTYPE html>

    <html lang="en">

    <head>

        <meta charset="UTF-8">

        <title>Update Record</title>

        <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">

        <style type="text/css">

            .wrapper{

                width: 500px;

                margin: 0 auto;

            }

        </style>

    </head>

    <body>

        <div class="wrapper">

            <div class="container-fluid">

                <div class="row">

                    <div class="col-md-12">

                        <div class="page-header">

                            <h2>Update Record</h2>

                        </div>

                        <p>Please edit the input values and submit to update the record.</p>

                        <form action="<?php echo htmlspecialchars(basename($_SERVER['REQUEST_URI'])); ?>" method="post">

                            <div class="form-group <?php echo (!empty($name_err)) ? 'has-error' : ''; ?>">

                                <label>Name</label>

                                <input type="text" name="name" class="form-control" value="<?php echo $name; ?>">

                                <span class="help-block"><?php echo $name_err;?></span>

                            </div>

                            <div class="form-group <?php echo (!empty($address_err)) ? 'has-error' : ''; ?>">

                                <label>Address</label>

                                <textarea name="address" class="form-control"><?php echo $address; ?></textarea>

                                <span class="help-block"><?php echo $address_err;?></span>

                            </div>

                            <div class="form-group <?php echo (!empty($salary_err)) ? 'has-error' : ''; ?>">

                                <label>Title</label>

                                <input type="text" name="salary" class="form-control" value="<?php echo $salary; ?>">

                                <span class="help-block"><?php echo $salary_err;?></span>

                            </div>

                            <input type="hidden" name="id" value="<?php echo $id; ?>"/>

                            <input type="submit" class="btn btn-primary" value="Submit">

                            <a href="index.php" class="btn btn-default">Cancel</a>

                        </form>

                    </div>

                </div>        

            </div>

        </div>

    </body>

    </html>