Tuesday 10 July 2018

PHP - View, Edit, Add, Delete records with MySQLi

How to create a system that allows a user to add/edit/remove data in a database seems to be a commonly asked topic, so I may adapt this into an actual tutorial at some point in the future.

DATABASE:
-- You'll need to create a database (I named mine 'records' but it can be changed) using PHPMyAdmin
-- Save the included sql file on your desktop as a .txt file
-- Once you've created the database, make sure the database is selected, then click the "import" tab
-- Select the .txt file on your desktop, and import it into your database. PHPMyAdmin will create all of the necessary tables/import some test data for you to play with

SQL file:
--
-- Table structure for table `players`
--

CREATE TABLE `players` (
`id` int(11) NOT NULL auto_increment,
`firstname` varchar(32) NOT NULL,
`lastname` varchar(32) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=5 ;

--
-- Dumping data for table `players`
--

INSERT INTO `players` VALUES(1, 'Bob', 'Baker');
INSERT INTO `players` VALUES(2, 'Tim', 'Thomas');
INSERT INTO `players` VALUES(3, 'Rachel', 'Roberts');
INSERT INTO `players` VALUES(4, 'Sam', 'Smith');
Save these php files all in the same folder in a place where you can run them using your server (I'm assuming you are using something like WAMP for the server? I'm not sure if Dreamweaver includes something like that by default.)

connect-db.php
<?php

// server info
$server = 'localhost';
$user = 'root';
$pass = 'root';
$db = 'records2';

// connect to the database
$mysqli = new mysqli($server, $user, $pass, $db);

// show errors (remove this line if on a live site)
mysqli_report(MYSQLI_REPORT_ERROR);

?>
view.php (non-paginated -- will just display one long list of members)

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>View Records</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
</head>
<body>

<h1>View Records</h1>

<p><b>View All</b> | <a href="view-paginated.php">View Paginated</a></p>

<?php
// connect to the database
include('connect-db.php');

// get the records from the database
if ($result = $mysqli->query("SELECT * FROM players ORDER BY id"))
{
// display records if there are records to display
if ($result->num_rows > 0)
{
// display records in a table
echo "<table border='1' cellpadding='10'>";

// set table headers
echo "<tr><th>ID</th><th>First Name</th><th>Last Name</th><th></th><th></th></tr>";

while ($row = $result->fetch_object())
{
// set up a row for each record
echo "<tr>";
echo "<td>" . $row->id . "</td>";
echo "<td>" . $row->firstname . "</td>";
echo "<td>" . $row->lastname . "</td>";
echo "<td><a href='records.php?id=" . $row->id . "'>Edit</a></td>";
echo "<td><a href='delete.php?id=" . $row->id . "'>Delete</a></td>";
echo "</tr>";
}

echo "</table>";
}
// if there are no records in the database, display an alert message
else
{
echo "No results to display!";
}
}
// show an error if there is an issue with the database query
else
{
echo "Error: " . $mysqli->error;
}

// close database connection
$mysqli->close();

?>

<a href="records.php">Add New Record</a>
</body>
</html>
view-paginated.php

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>View Records</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
</head>
<body>

<h1>View Records</h1>

<?php
// connect to the database
include('connect-db.php');

// number of results to show per page
$per_page = 3;

// figure out the total pages in the database
if ($result = $mysqli->query("SELECT * FROM players ORDER BY id"))
{
if ($result->num_rows != 0)
{
$total_results = $result->num_rows;
// ceil() returns the next highest integer value by rounding up value if necessary
$total_pages = ceil($total_results / $per_page);

// check if the 'page' variable is set in the URL (ex: view-paginated.php?page=1)
if (isset($_GET['page']) && is_numeric($_GET['page']))
{
$show_page = $_GET['page'];

// make sure the $show_page value is valid
if ($show_page > 0 && $show_page <= $total_pages)
{
$start = ($show_page -1) * $per_page;
$end = $start + $per_page;
}
else
{
// error - show first set of results
$start = 0;
$end = $per_page;
}
}
else
{
// if page isn't set, show first set of results
$start = 0;
$end = $per_page;
}

// display pagination
echo "<p><a href='view.php'>View All</a> | <b>View Page:</b> ";
for ($i = 1; $i <= $total_pages; $i++)
{
if (isset($_GET['page']) && $_GET['page'] == $i)
{
echo $i . " ";
}
else
{
echo "<a href='view-paginated.php?page=$i'>$i</a> ";
}
}
echo "</p>";

// display data in table
echo "<table border='1' cellpadding='10'>";
echo "<tr> <th>ID</th> <th>First Name</th> <th>Last Name</th> <th></th> <th></th></tr>";

// loop through results of database query, displaying them in the table
for ($i = $start; $i < $end; $i++)
{
// make sure that PHP doesn't try to show results that don't exist
if ($i == $total_results) { break; }

// find specific row
$result->data_seek($i);
$row = $result->fetch_row();

// echo out the contents of each row into a table
echo "<tr>";
echo '<td>' . $row[0] . '</td>';
echo '<td>' . $row[1] . '</td>';
echo '<td>' . $row[2] . '</td>';
echo '<td><a href="records.php?id=' . $row[0] . '">Edit</a></td>';
echo '<td><a href="delete.php?id=' . $row[0] . '">Delete</a></td>';
echo "</tr>";
}

// close table>
echo "</table>";
}
else
{
echo "No results to display!";
}
}
// error with the query
else
{
echo "Error: " . $mysqli->error;
}

// close database connection
$mysqli->close();

?>

<a href="records.php">Add New Record</a>
</body>
</html>
</html>
records.php (create a new record/edit existing records)

<?php
/*
Allows the user to both create new records and edit existing records
*/

// connect to the database
include("connect-db.php");

// creates the new/edit record form
// since this form is used multiple times in this file, I have made it a function that is easily reusable
function renderForm($first = '', $last ='', $error = '', $id = '')
{ ?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>
<?php if ($id != '') { echo "Edit Record"; } else { echo "New Record"; } ?>
</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
</head>
<body>
<h1><?php if ($id != '') { echo "Edit Record"; } else { echo "New Record"; } ?></h1>
<?php if ($error != '') {
echo "<div style='padding:4px; border:1px solid red; color:red'>" . $error
. "</div>";
} ?>

<form action="" method="post">
<div>
<?php if ($id != '') { ?>
<input type="hidden" name="id" value="<?php echo $id; ?>" />
<p>ID: <?php echo $id; ?></p>
<?php } ?>

<strong>First Name: *</strong> <input type="text" name="firstname"
value="<?php echo $first; ?>"/><br/>
<strong>Last Name: *</strong> <input type="text" name="lastname"
value="<?php echo $last; ?>"/>
<p>* required</p>
<input type="submit" name="submit" value="Submit" />
</div>
</form>
</body>
</html>

<?php }



/*

EDIT RECORD

*/
// if the 'id' variable is set in the URL, we know that we need to edit a record
if (isset($_GET['id']))
{
// if the form's submit button is clicked, we need to process the form
if (isset($_POST['submit']))
{
// make sure the 'id' in the URL is valid
if (is_numeric($_POST['id']))
{
// get variables from the URL/form
$id = $_POST['id'];
$firstname = htmlentities($_POST['firstname'], ENT_QUOTES);
$lastname = htmlentities($_POST['lastname'], ENT_QUOTES);

// check that firstname and lastname are both not empty
if ($firstname == '' || $lastname == '')
{
// if they are empty, show an error message and display the form
$error = 'ERROR: Please fill in all required fields!';
renderForm($firstname, $lastname, $error, $id);
}
else
{
// if everything is fine, update the record in the database
if ($stmt = $mysqli->prepare("UPDATE players SET firstname = ?, lastname = ?
WHERE id=?"))
{
$stmt->bind_param("ssi", $firstname, $lastname, $id);
$stmt->execute();
$stmt->close();
}
// show an error message if the query has an error
else
{
echo "ERROR: could not prepare SQL statement.";
}

// redirect the user once the form is updated
header("Location: view.php");
}
}
// if the 'id' variable is not valid, show an error message
else
{
echo "Error!";
}
}
// if the form hasn't been submitted yet, get the info from the database and show the form
else
{
// make sure the 'id' value is valid
if (is_numeric($_GET['id']) && $_GET['id'] > 0)
{
// get 'id' from URL
$id = $_GET['id'];

// get the recod from the database
if($stmt = $mysqli->prepare("SELECT * FROM players WHERE id=?"))
{
$stmt->bind_param("i", $id);
$stmt->execute();

$stmt->bind_result($id, $firstname, $lastname);
$stmt->fetch();

// show the form
renderForm($firstname, $lastname, NULL, $id);

$stmt->close();
}
// show an error if the query has an error
else
{
echo "Error: could not prepare SQL statement";
}
}
// if the 'id' value is not valid, redirect the user back to the view.php page
else
{
header("Location: view.php");
}
}
}



/*

NEW RECORD

*/
// if the 'id' variable is not set in the URL, we must be creating a new record
else
{
// if the form's submit button is clicked, we need to process the form
if (isset($_POST['submit']))
{
// get the form data
$firstname = htmlentities($_POST['firstname'], ENT_QUOTES);
$lastname = htmlentities($_POST['lastname'], ENT_QUOTES);

// check that firstname and lastname are both not empty
if ($firstname == '' || $lastname == '')
{
// if they are empty, show an error message and display the form
$error = 'ERROR: Please fill in all required fields!';
renderForm($firstname, $lastname, $error);
}
else
{
// insert the new record into the database
if ($stmt = $mysqli->prepare("INSERT players (firstname, lastname) VALUES (?, ?)"))
{
$stmt->bind_param("ss", $firstname, $lastname);
$stmt->execute();
$stmt->close();
}
// show an error if the query has an error
else
{
echo "ERROR: Could not prepare SQL statement.";
}

// redirec the user
header("Location: view.php");
}

}
// if the form hasn't been submitted yet, show the form
else
{
renderForm();
}
}

// close the mysqli connection
$mysqli->close();
?>
delete.php

<?php

// connect to the database
include('connect-db.php');

// confirm that the 'id' variable has been set
if (isset($_GET['id']) && is_numeric($_GET['id']))
{
// get the 'id' variable from the URL
$id = $_GET['id'];

// delete record from database
if ($stmt = $mysqli->prepare("DELETE FROM players WHERE id = ? LIMIT 1"))
{
$stmt->bind_param("i",$id);
$stmt->execute();
$stmt->close();
}
else
{
echo "ERROR: could not prepare SQL statement.";
}
$mysqli->close();

// redirect user after delete is successful
header("Location: view.php");
}
else
// if the 'id' variable isn't set, redirect the user
{
header("Location: view.php");
}

?>

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