What is CRUD in PHP(Server Side Scripting Language)
CRUD is an acronym for Create, Read, Update, and Delete. CRUD operations are basic data manipulation for database. In this tutorial we'll create a simple PHP application to perform all these operations on a MySQL database table at one place.
CRUD refers to the four basic types of Database operations: Create, Read, Update, Delete. Most applications and projects perform some kind of CRUD functionality.
Once you learn about these CRUD operations, you can use them for many projects. For an example, if you learn how to create student table with multiple columns, you can use similar approach to create employee table or customers table.
Well, let's start by creating the table which we'll use in all of our example.
Creating the Database Table
Execute the following SQL query to create a table named employees inside your MySQL database.
CREATE TABLE employees ( id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, name VARCHAR(100) NOT NULL, address VARCHAR(255) NOT NULL, salary INT(10) NOT NULL);
After creating the table, we need create a PHP script in order to connect to the MySQL database server. Let's create a file named "config.php" and put the following code inside it.
Creating the Config File
<?phpdefine('DB_SERVER', 'localhost');define('DB_USERNAME', 'root');define('DB_PASSWORD', '');define('DB_NAME', 'demo'); $link = mysqli_connect(DB_SERVER, DB_USERNAME, DB_PASSWORD, DB_NAME); if($link === false){ die("ERROR: Could not connect. " . mysqli_connect_error());}?>
We'll later include this config file in other pages using the PHP require_once() function.
Note: Replace the credentials according to your MySQL server setting before testing this code, for example, replace the database name 'demo' with your own database name, replace username 'root' with your own database username, specify database password if there's any.
First we will create a landing page for our CRUD application that contains a data grid showing the records from the employees database table. It also has action icons for each record displayed in the grid, that you may choose to view its details, update it, or delete it.
We'll also add a create button on the top of the data grid that can be used for creating new records in the employees table. Create a file named "index.php" and put the following code in it:
Creating the Landing Page
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Dashboard</title><link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css"> <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css"> <script src="https://code.jquery.com/jquery-3.5.1.min.js"></script> <script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.1/dist/umd/popper.min.js"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script> <style> .wrapper{ width: 600px; margin: 0 auto; } table tr td:last-child{ width: 120px; } </style> <script> $(document).ready(function(){ $('[data-toggle="tooltip"]').tooltip(); }); </script></head><body> <div class="wrapper"> <div class="container-fluid"> <div class="row"> <div class="col-md-12"> <div class="mt-5 mb-3 clearfix"> <h2 class="pull-left">Employees Details</h2> <a href="create.php" class="btn btn-success pull-right"><i class="fa fa-plus"></i> Add New Employee</a> </div> <?php require_once "config.php"; $sql = "SELECT * FROM employees"; if($result = mysqli_query($link, $sql)){ if(mysqli_num_rows($result) > 0){ echo '<table class="table table-bordered table-striped">'; echo "<thead>"; echo "<tr>"; echo "<th>#</th>"; echo "<th>Name</th>"; echo "<th>Address</th>"; echo "<th>Salary</th>"; echo "<th>Action</th>"; echo "</tr>"; echo "</thead>"; echo "<tbody>"; while($row = mysqli_fetch_array($result)){ echo "<tr>"; echo "<td>" . $row['id'] . "</td>"; echo "<td>" . $row['name'] . "</td>"; echo "<td>" . $row['address'] . "</td>"; echo "<td>" . $row['salary'] . "</td>"; echo "<td>"; echo '<a href="read.php?id='. $row['id'] .'" class="mr-3" title="View Record" data-toggle="tooltip"><span class="fa fa-eye"></span></a>'; echo '<a href="update.php?id='. $row['id'] .'" class="mr-3" title="Update Record" data-toggle="tooltip"><span class="fa fa-pencil"></span></a>'; echo '<a href="delete.php?id='. $row['id'] .'" title="Delete Record" data-toggle="tooltip"><span class="fa fa-trash"></span></a>'; echo "</td>"; echo "</tr>"; } echo "</tbody>"; echo "</table>"; mysqli_free_result($result); } else{ echo '<div class="alert alert-danger"><em>No records were found.</em></div>'; } } else{ echo "Oops! Something went wrong. Please try again later."; } mysqli_close($link); ?> </div> </div> </div> </div></body></html>
Tip: We've used the Bootstrap framework to make this CRUD application layout quickly and beautifully. Bootstrap is the most popular and powerful front-end framework for faster and easier responsive web development. Please, checkout the Bootstrap tutorial section to learn more about this framework.
Creating the Create Page
In this section we'll build the Create functionality of our CRUD application.
Let's create a file named "create.php" and put the following code inside it. It will generate a web form that can be used to insert records in the employees table.
<?phprequire_once "config.php"; $name = $address = $salary = "";$name_err = $address_err = $salary_err = ""; if($_SERVER["REQUEST_METHOD"] == "POST"){ $input_name = trim($_POST["name"]); if(empty($input_name)){ $name_err = "Please enter a name."; } elseif(!filter_var($input_name, FILTER_VALIDATE_REGEXP, array("options"=>array("regexp"=>"/^[a-zA-Z\s]+$/")))){ $name_err = "Please enter a valid name."; } else{ $name = $input_name; } $input_address = trim($_POST["address"]); if(empty($input_address)){ $address_err = "Please enter an address."; } else{ $address = $input_address; } $input_salary = trim($_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 = $input_salary; } if(empty($name_err) && empty($address_err) && empty($salary_err)){ $sql = "INSERT INTO employees (name, address, salary) VALUES (?, ?, ?)"; if($stmt = mysqli_prepare($link, $sql)){ mysqli_stmt_bind_param($stmt, "sss", $param_name, $param_address, $param_salary); $param_name = $name; $param_address = $address; $param_salary = $salary; if(mysqli_stmt_execute($stmt)){ header("location: index.php"); exit(); } else{ echo "Oops! Something went wrong. Please try again later."; } } mysqli_stmt_close($stmt); } mysqli_close($link);}?> <!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Create Record</title> <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css"> <style> .wrapper{ width: 600px; margin: 0 auto; } </style></head><body> <div class="wrapper"> <div class="container-fluid"> <div class="row"> <div class="col-md-12"> <h2 class="mt-5">Create Record</h2> <p>Please fill this form and submit to add employee record to the database.</p> <form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post"> <div class="form-group"> <label>Name</label> <input type="text" name="name" class="form-control <?php echo (!empty($name_err)) ? 'is-invalid' : ''; ?>" value="<?php echo $name; ?>"> <span class="invalid-feedback"><?php echo $name_err;?></span> </div> <div class="form-group"> <label>Address</label> <textarea name="address" class="form-control <?php echo (!empty($address_err)) ? 'is-invalid' : ''; ?>"><?php echo $address; ?></textarea> <span class="invalid-feedback"><?php echo $address_err;?></span> </div> <div class="form-group"> <label>Salary</label> <input type="text" name="salary" class="form-control <?php echo (!empty($salary_err)) ? 'is-invalid' : ''; ?>" value="<?php echo $salary; ?>"> <span class="invalid-feedback"><?php echo $salary_err;?></span> </div> <input type="submit" class="btn btn-primary" value="Submit"> <a href="index.php" class="btn btn-secondary ml-2">Cancel</a> </form> </div> </div> </div> </div></body></html>
The same "create.php" file will display the HTML form and process the submitted form data. It will also perform basic validation on user inputs before saving the data.
Creating the Read Page
Now it's time to build the Read functionality of our CRUD application.
Let's create a file named "read.php" and put the following code inside it. It will simply retrieve the records from the employees table based the id attribute of the employee.
<?phpif(isset($_GET["id"]) && !empty(trim($_GET["id"]))){ require_once "config.php"; $sql = "SELECT * FROM employees WHERE id = ?"; if($stmt = mysqli_prepare($link, $sql)){ mysqli_stmt_bind_param($stmt, "i", $param_id); $param_id = trim($_GET["id"]); if(mysqli_stmt_execute($stmt)){ $result = mysqli_stmt_get_result($stmt); if(mysqli_num_rows($result) == 1){ $row = mysqli_fetch_array($result, MYSQLI_ASSOC); $name = $row["name"]; $address = $row["address"]; $salary = $row["salary"]; } else{ header("location: error.php"); exit(); } } else{ echo "Oops! Something went wrong. Please try again later."; } } mysqli_stmt_close($stmt); mysqli_close($link);} else{ header("location: error.php"); exit();}?><!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>View Record</title> <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css"> <style> .wrapper{ width: 600px; margin: 0 auto; } </style></head><body> <div class="wrapper"> <div class="container-fluid"> <div class="row"> <div class="col-md-12"> <h1 class="mt-5 mb-3">View Record</h1> <div class="form-group"> <label>Name</label> <p><b><?php echo $row["name"]; ?></b></p> </div> <div class="form-group"> <label>Address</label> <p><b><?php echo $row["address"]; ?></b></p> </div> <div class="form-group"> <label>Salary</label> <p><b><?php echo $row["salary"]; ?></b></p> </div> <p><a href="index.php" class="btn btn-primary">Back</a></p> </div> </div> </div> </div></body></html>
Creating the Update Page
Similarly, we can build the Update functionality of our CRUD application.
Let's create a file named "update.php" and put the following code inside it. It will update the existing records in the employees table based the id attribute of the employee.
<?phprequire_once "config.php"; $name = $address = $salary = "";$name_err = $address_err = $salary_err = ""; if(isset($_POST["id"]) && !empty($_POST["id"])){ $id = $_POST["id"]; $input_name = trim($_POST["name"]); if(empty($input_name)){ $name_err = "Please enter a name."; } elseif(!filter_var($input_name, FILTER_VALIDATE_REGEXP, array("options"=>array("regexp"=>"/^[a-zA-Z\s]+$/")))){ $name_err = "Please enter a valid name."; } else{ $name = $input_name; } $input_address = trim($_POST["address"]); if(empty($input_address)){ $address_err = "Please enter an address."; } else{ $address = $input_address; } $input_salary = trim($_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 = $input_salary; } if(empty($name_err) && empty($address_err) && empty($salary_err)){ $sql = "UPDATE employees SET name=?, address=?, salary=? WHERE id=?"; if($stmt = mysqli_prepare($link, $sql)){ mysqli_stmt_bind_param($stmt, "sssi", $param_name, $param_address, $param_salary, $param_id); $param_name = $name; $param_address = $address; $param_salary = $salary; $param_id = $id; if(mysqli_stmt_execute($stmt)){ header("location: index.php"); exit(); } else{ echo "Oops! Something went wrong. Please try again later."; } } mysqli_stmt_close($stmt); } mysqli_close($link);} else{ if(isset($_GET["id"]) && !empty(trim($_GET["id"]))){ $id = trim($_GET["id"]); $sql = "SELECT * FROM employees WHERE id = ?"; if($stmt = mysqli_prepare($link, $sql)){ mysqli_stmt_bind_param($stmt, "i", $param_id); $param_id = $id; if(mysqli_stmt_execute($stmt)){ $result = mysqli_stmt_get_result($stmt); if(mysqli_num_rows($result) == 1){ $row = mysqli_fetch_array($result, MYSQLI_ASSOC); $name = $row["name"]; $address = $row["address"]; $salary = $row["salary"]; } else{ header("location: error.php"); exit(); } } else{ echo "Oops! Something went wrong. Please try again later."; } } mysqli_stmt_close($stmt); mysqli_close($link); } else{ header("location: error.php"); exit(); }}?> <!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Update Record</title> <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css"> <style> .wrapper{ width: 600px; margin: 0 auto; } </style></head><body> <div class="wrapper"> <div class="container-fluid"> <div class="row"> <div class="col-md-12"> <h2 class="mt-5">Update Record</h2> <p>Please edit the input values and submit to update the employee record.</p> <form action="<?php echo htmlspecialchars(basename($_SERVER['REQUEST_URI'])); ?>" method="post"> <div class="form-group"> <label>Name</label> <input type="text" name="name" class="form-control <?php echo (!empty($name_err)) ? 'is-invalid' : ''; ?>" value="<?php echo $name; ?>"> <span class="invalid-feedback"><?php echo $name_err;?></span> </div> <div class="form-group"> <label>Address</label> <textarea name="address" class="form-control <?php echo (!empty($address_err)) ? 'is-invalid' : ''; ?>"><?php echo $address; ?></textarea> <span class="invalid-feedback"><?php echo $address_err;?></span> </div> <div class="form-group"> <label>Salary</label> <input type="text" name="salary" class="form-control <?php echo (!empty($salary_err)) ? 'is-invalid' : ''; ?>" value="<?php echo $salary; ?>"> <span class="invalid-feedback"><?php echo $salary_err;?></span> </div> <input type="hidden" name="id" value="<?php echo $id; ?>"/> <input type="submit" class="btn btn-primary" value="Submit"> <a href="index.php" class="btn btn-secondary ml-2">Cancel</a> </form> </div> </div> </div> </div></body></html>
Creating the Delete Page
Finally, we will build the Delete functionality of our CRUD application.
Let's create a file named "delete.php" and put the following code inside it. It will delete the existing records from the employees table based the id attribute of the employee.
<?phpif(isset($_POST["id"]) && !empty($_POST["id"])){ require_once "config.php"; $sql = "DELETE FROM employees WHERE id = ?"; if($stmt = mysqli_prepare($link, $sql)){ mysqli_stmt_bind_param($stmt, "i", $param_id); $param_id = trim($_POST["id"]); if(mysqli_stmt_execute($stmt)){ header("location: index.php"); exit(); } else{ echo "Oops! Something went wrong. Please try again later."; } } mysqli_stmt_close($stmt); mysqli_close($link);} else{ if(empty(trim($_GET["id"]))){ header("location: error.php"); exit(); }}?><!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Delete Record</title> <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css"> <style> .wrapper{ width: 600px; margin: 0 auto; } </style></head><body> <div class="wrapper"> <div class="container-fluid"> <div class="row"> <div class="col-md-12"> <h2 class="mt-5 mb-3">Delete Record</h2> <form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post"> <div class="alert alert-danger"> <input type="hidden" name="id" value="<?php echo trim($_GET["id"]); ?>"/> <p>Are you sure you want to delete this employee record?</p> <p> <input type="submit" value="Yes" class="btn btn-danger"> <a href="index.php" class="btn btn-secondary">No</a> </p> </div> </form> </div> </div> </div> </div></body></html>
Creating the Error Page
At the end, let's create one more file "error.php". This page will be displayed if request is invalid i.e. if id parameter is missing from the URL query string or it is not valid.
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Error</title> <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css"> <style> .wrapper{ width: 600px; margin: 0 auto; } </style></head><body> <div class="wrapper"> <div class="container-fluid"> <div class="row"> <div class="col-md-12"> <h2 class="mt-5 mb-3">Invalid Request</h2> <div class="alert alert-danger">Sorry, you've made an invalid request. Please <a href="index.php" class="alert-link">go back</a> and try again.</div> </div> </div> </div> </div></body></html>
After a long journey finally we've finished our CRUD application with PHP and MySQL.