PHP MySQL CRUD 应用程序

Created: October-16, 2018

在本教程中，你将学习如何使用 PHP 和 MySQL 构建 CRUD 应用程序。

什么是 CRUD

CRUD 是 Create，Read，Update 和 Delete 的首字母缩写。CRUD 操作是数据库的基本数据操作。我们已经学习了如何在前面的章节中执行创建（即插入），读取（即选择），更新和删除操作。在本教程中，我们将创建一个简单的 PHP 应用程序，以便在一个地方对 MySQL 数据库表执行所有这些操作。

好吧，让我们从创建我们将在我们所有示例中使用的表开始。

创建数据库表

执行以下 SQL 查询以在 MySQL 数据库中创建名为 employees 的表。我们将使用此表进行所有未来操作。

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
);

创建配置文件

创建表后，我们需要创建一个 PHP 脚本才能连接到 MySQL 数据库服务器。让我们创建一个名为 config.php 的文件，并在其中放入以下代码。

我们稍后将使用 PHP require_once() 函数将此配置文件包含在其他页面中。

面向过程式

<?php
/* Database credentials. Assuming you are running MySQL
server with default setting (user 'root' with no password) */
define('DB_SERVER', 'localhost');
define('DB_USERNAME', 'root');
define('DB_PASSWORD', '');
define('DB_NAME', 'demo');
 
/* Attempt to connect to MySQL database */
$link = mysqli_connect(DB_SERVER, DB_USERNAME, DB_PASSWORD, DB_NAME);
 
// Check connection
if($link === false){
    die("ERROR: Could not connect. " . mysqli_connect_error());
}
?>

面向对象式

<?php
/* Database credentials. Assuming you are running MySQL
server with default setting (user 'root' with no password) */
define('DB_SERVER', 'localhost');
define('DB_USERNAME', 'root');
define('DB_PASSWORD', '');
define('DB_NAME', 'demo');
 
/* Attempt to connect to MySQL database */
$mysqli = new mysqli(DB_SERVER, DB_USERNAME, DB_PASSWORD, DB_NAME);
 
// Check connection
if($mysqli === false){
    die("ERROR: Could not connect. " . $mysqli->connect_error);
}
?>

PDO 式

<?php
/* Database credentials. Assuming you are running MySQL
server with default setting (user 'root' with no password) */
define('DB_SERVER', 'localhost');
define('DB_USERNAME', 'root');
define('DB_PASSWORD', '');
define('DB_NAME', 'demo');
 
/* Attempt to connect to MySQL database */
try{
    $pdo = new PDO("mysql:host=" . DB_SERVER . ";dbname=" . DB_NAME, DB_USERNAME, DB_PASSWORD);
    // Set the PDO error mode to exception
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch(PDOException $e){
    die("ERROR: Could not connect. " . $e->getMessage());
}
?>

注意： 在测试此代码之前，请根据 MySQL 服务器设置为自己的配置，例如，将数据库名称’domo’替换为你自己的数据库名称，将 username root 替换为你自己的数据库用户名，如果有，请指定数据库密码。

创建着陆页

首先，我们将为 CRUD 应用程序创建一个登录页面，其中包含一个显示 employees 数据库表中记录的数据网格。它还为网格中显示的每条记录提供了操作图标，你可以选择查看其详细信息，更新或删除它们。

我们还将在数据网格的顶部添加一个创建按钮，该按钮可用于在 employees 表中创建新记录。创建一个名为 index.php 的文件，并在其中放入以下代码：

面向过程式

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Dashboard</title>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.js"></script>
    <style type="text/css">
        .wrapper{
            width: 650px;
            margin: 0 auto;
        }
        .page-header h2{
            margin-top: 0;
        }
        table tr td:last-child a{
            margin-right: 15px;
        }
    </style>
    <script type="text/javascript">
        $(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="page-header clearfix">
                        <h2 class="pull-left">Employees Details</h2>
                        <a href="create.php" class="btn btn-success pull-right">Add New Employee</a>
                    </div>
                    <?php
                    // Include config file
                    require_once "config.php";
                    
                    // Attempt select query execution
                    $sql = "SELECT * FROM employees";
                    if($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'] ."' title='View Record' data-toggle='tooltip'><span class='glyphicon glyphicon-eye-open'></span></a>";
                                            echo "<a href='update.php?id=". $row['id'] ."' title='Update Record' data-toggle='tooltip'><span class='glyphicon glyphicon-pencil'></span></a>";
                                            echo "<a href='delete.php?id=". $row['id'] ."' title='Delete Record' data-toggle='tooltip'><span class='glyphicon glyphicon-trash'></span></a>";
                                        echo "</td>";
                                    echo "</tr>";
                                }
                                echo "</tbody>";                            
                            echo "</table>";
                            // Free result set
                            mysqli_free_result($result);
                        } else{
                            echo "<p class='lead'><em>No records were found.</em></p>";
                        }
                    } else{
                        echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
                    }
 
                    // Close connection
                    mysqli_close($link);
                    ?>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

面向对象式

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Dashboard</title>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.js"></script>
    <style type="text/css">
        .wrapper{
            width: 650px;
            margin: 0 auto;
        }
        .page-header h2{
            margin-top: 0;
        }
        table tr td:last-child a{
            margin-right: 15px;
        }
    </style>
    <script type="text/javascript">
        $(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="page-header clearfix">
                        <h2 class="pull-left">Employees Details</h2>
                        <a href="create.php" class="btn btn-success pull-right">Add New Employee</a>
                    </div>
                    <?php
                    // Include config file
                    require_once "config.php";
                    
                    // Attempt select query execution
                    $sql = "SELECT * FROM employees";
                    if($result = $mysqli->query($sql)){
                        if($result->num_rows > 0){
                            echo "<table class='table table-bordered table-striped'>";
                                echo "<thead>";
                                    echo "<tr>";
                                        echo "<th>#</th>";
                                        echo "<th>Name</th>";
                                        echo "<th>Address</th>";
                                        echo "<th>Salary</th>";
                                        echo "<th>Action</th>";
                                    echo "</tr>";
                                echo "</thead>";
                                echo "<tbody>";
                                while($row = $result->fetch_array()){
                                    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'] ."' title='View Record' data-toggle='tooltip'><span class='glyphicon glyphicon-eye-open'></span></a>";
                                            echo "<a href='update.php?id=". $row['id'] ."' title='Update Record' data-toggle='tooltip'><span class='glyphicon glyphicon-pencil'></span></a>";
                                            echo "<a href='delete.php?id=". $row['id'] ."' title='Delete Record' data-toggle='tooltip'><span class='glyphicon glyphicon-trash'></span></a>";
                                        echo "</td>";
                                    echo "</tr>";
                                }
                                echo "</tbody>";                            
                            echo "</table>";
                            // Free result set
                            $result->free();
                        } else{
                            echo "<p class='lead'><em>No records were found.</em></p>";
                        }
                    } else{
                        echo "ERROR: Could not able to execute $sql. " . $mysqli->error;
                    }
                    
                    // Close connection
                    $mysqli->close();
                    ?>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

PDO 式

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Dashboard</title>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.js"></script>
    <style type="text/css">
        .wrapper{
            width: 650px;
            margin: 0 auto;
        }
        .page-header h2{
            margin-top: 0;
        }
        table tr td:last-child a{
            margin-right: 15px;
        }
    </style>
    <script type="text/javascript">
        $(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="page-header clearfix">
                        <h2 class="pull-left">Employees Details</h2>
                        <a href="create.php" class="btn btn-success pull-right">Add New Employee</a>
                    </div>
                    <?php
                    // Include config file
                    require_once "config.php";
                    
                    // Attempt select query execution
                    $sql = "SELECT * FROM employees";
                    if($result = $pdo->query($sql)){
                        if($result->rowCount() > 0){
                            echo "<table class='table table-bordered table-striped'>";
                                echo "<thead>";
                                    echo "<tr>";
                                        echo "<th>#</th>";
                                        echo "<th>Name</th>";
                                        echo "<th>Address</th>";
                                        echo "<th>Salary</th>";
                                        echo "<th>Action</th>";
                                    echo "</tr>";
                                echo "</thead>";
                                echo "<tbody>";
                                while($row = $result->fetch()){
                                    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'] ."' title='View Record' data-toggle='tooltip'><span class='glyphicon glyphicon-eye-open'></span></a>";
                                            echo "<a href='update.php?id=". $row['id'] ."' title='Update Record' data-toggle='tooltip'><span class='glyphicon glyphicon-pencil'></span></a>";
                                            echo "<a href='delete.php?id=". $row['id'] ."' title='Delete Record' data-toggle='tooltip'><span class='glyphicon glyphicon-trash'></span></a>";
                                        echo "</td>";
                                    echo "</tr>";
                                }
                                echo "</tbody>";                            
                            echo "</table>";
                            // Free result set
                            unset($result);
                        } else{
                            echo "<p class='lead'><em>No records were found.</em></p>";
                        }
                    } else{
                        echo "ERROR: Could not able to execute $sql. " . $mysqli->error;
                    }
                    
                    // Close connection
                    unset($pdo);
                    ?>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

一旦 employees 表填充了一些记录，登陆页面即 CRUD 数据网格可能如下图所示：

PHP MySQL CRUD 网格

提示： 我们已经使用 Bootstrap 框架快速而精美地制作了这个 CRUD 应用程序布局。Bootstrap 是最流行和最强大的前端框架，可以更快，更轻松地响应 Web 开发。请查看 Bootstrap 教程部分以了解有关此框架的更多信息。

创建 `Create` 页面

在本节中，我们将构建 CRUD 应用程序的 Create 功能。

让我们创建一个名为 create.php 的文件，并在其中放入以下代码。它将生成一个 Web 表单，可用于在 employees 表中插入记录。

面向过程式

<?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($_SERVER["REQUEST_METHOD"] == "POST"){
    // Validate name
    $input_name = trim($_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;
    }
    
    // Validate 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 insert statement
        $sql = "INSERT INTO employees (name, address, salary) VALUES (?, ?, ?)";
         
        if($stmt = mysqli_prepare($link, $sql)){
            // Bind variables to the prepared statement as parameters
            mysqli_stmt_bind_param($stmt, "sss", $param_name, $param_address, $param_salary);
            
            // Set parameters
            $param_name = $name;
            $param_address = $address;
            $param_salary = $salary;
            
            // Attempt to execute the prepared statement
            if(mysqli_stmt_execute($stmt)){
                // Records created 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);
}
?>
 
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Create 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>Create Record</h2>
                    </div>
                    <p>Please fill this form and submit to add employee record to the database.</p>
                    <form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
                        <div class="form-group <?php echo (!empty($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>Salary</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="submit" class="btn btn-primary" value="Submit">
                        <a href="index.php" class="btn btn-default">Cancel</a>
                    </form>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

面向对象式

<?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($_SERVER["REQUEST_METHOD"] == "POST"){
    // Validate name
    $input_name = trim($_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;
    }
    
    // Validate 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 insert statement
        $sql = "INSERT INTO employees (name, address, salary) VALUES (?, ?, ?)";
 
        if($stmt = $mysqli->prepare($sql)){
            // Bind variables to the prepared statement as parameters
            $stmt->bind_param("sss", $param_name, $param_address, $param_salary);
            
            // Set parameters
            $param_name = $name;
            $param_address = $address;
            $param_salary = $salary;
            
            // Attempt to execute the prepared statement
            if($stmt->execute()){
                // Records created successfully. Redirect to landing page
                header("location: index.php");
                exit();
            } else{
                echo "Something went wrong. Please try again later.";
            }
        }
         
        // Close statement
        $stmt->close();
    }
    
    // Close connection
    $mysqli->close();
}
?>
 
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Create 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>Create Record</h2>
                    </div>
                    <p>Please fill this form and submit to add employee record to the database.</p>
                    <form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
                        <div class="form-group <?php echo (!empty($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>Salary</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="submit" class="btn btn-primary" value="Submit">
                        <a href="index.php" class="btn btn-default">Cancel</a>
                    </form>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

PDO 式

<?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($_SERVER["REQUEST_METHOD"] == "POST"){
    // Validate name
    $input_name = trim($_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;
    }
    
    // Validate 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 insert statement
        $sql = "INSERT INTO employees (name, address, salary) VALUES (:name, :address, :salary)";
 
        if($stmt = $pdo->prepare($sql)){
            // Bind variables to the prepared statement as parameters
            $stmt->bindParam(":name", $param_name);
            $stmt->bindParam(":address", $param_address);
            $stmt->bindParam(":salary", $param_salary);
            
            // Set parameters
            $param_name = $name;
            $param_address = $address;
            $param_salary = $salary;
            
            // Attempt to execute the prepared statement
            if($stmt->execute()){
                // Records created successfully. Redirect to landing page
                header("location: index.php");
                exit();
            } else{
                echo "Something went wrong. Please try again later.";
            }
        }
         
        // Close statement
        unset($stmt);
    }
    
    // Close connection
    unset($pdo);
}
?>
 
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Create 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>Create Record</h2>
                    </div>
                    <p>Please fill this form and submit to add employee record to the database.</p>
                    <form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
                        <div class="form-group <?php echo (!empty($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>Salary</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="submit" class="btn btn-primary" value="Submit">
                        <a href="index.php" class="btn btn-default">Cancel</a>
                    </form>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

相同的 create.php 文件将显示 HTML 表单并处理提交的表单数据。在保存数据之前，它还将对用户输入（第 11 行至第 37 行）执行基本验证。

创建阅读页面

现在是时候构建我们的 CRUD 应用程序的 Read 功能了。

让我们创建一个名为 create.php 的文件，并在其中放入以下代码。它将根据 employees 的 id 属性从 employees 表中检索记录。

面向过程式

<?php
// Check existence of id parameter before processing further
if(isset($_GET["id"]) && !empty(trim($_GET["id"]))){
    // Include config file
    require_once "config.php";
    
    // Prepare a select statement
    $sql = "SELECT * FROM employees WHERE 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
        $param_id = trim($_GET["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["address"];
                $salary = $row["salary"];
            } else{
                // URL doesn't contain valid id parameter. 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>View 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">
                        <h1>View Record</h1>
                    </div>
                    <div class="form-group">
                        <label>Name</label>
                        <p class="form-control-static"><?php echo $row["name"]; ?></p>
                    </div>
                    <div class="form-group">
                        <label>Address</label>
                        <p class="form-control-static"><?php echo $row["address"]; ?></p>
                    </div>
                    <div class="form-group">
                        <label>Salary</label>
                        <p class="form-control-static"><?php echo $row["salary"]; ?></p>
                    </div>
                    <p><a href="index.php" class="btn btn-primary">Back</a></p>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

面向对象式

<?php
// Check existence of id parameter before processing further
if(isset($_GET["id"]) && !empty(trim($_GET["id"]))){
    // Include config file
    require_once "config.php";
    
    // Prepare a select statement
    $sql = "SELECT * FROM employees WHERE id = ?";
    
    if($stmt = $mysqli->prepare($sql)){
        // Bind variables to the prepared statement as parameters
        $stmt->bind_param("i", $param_id);
        
        // Set parameters
        $param_id = trim($_GET["id"]);
        
        // Attempt to execute the prepared statement
        if($stmt->execute()){
            $result = $stmt->get_result();
            
            if($result->num_rows == 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 = $result->fetch_array(MYSQLI_ASSOC);
                
                // Retrieve individual field value
                $name = $row["name"];
                $address = $row["address"];
                $salary = $row["salary"];
            } else{
                // URL doesn't contain valid id parameter. Redirect to error page
                header("location: error.php");
                exit();
            }
            
        } else{
            echo "Oops! Something went wrong. Please try again later.";
        }
    }
     
    // Close statement
    $stmt->close();
    
    // Close connection
    $mysqli->close();
} 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>View 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">
                        <h1>View Record</h1>
                    </div>
                    <div class="form-group">
                        <label>Name</label>
                        <p class="form-control-static"><?php echo $row["name"]; ?></p>
                    </div>
                    <div class="form-group">
                        <label>Address</label>
                        <p class="form-control-static"><?php echo $row["address"]; ?></p>
                    </div>
                    <div class="form-group">
                        <label>Salary</label>
                        <p class="form-control-static"><?php echo $row["salary"]; ?></p>
                    </div>
                    <p><a href="index.php" class="btn btn-primary">Back</a></p>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

PDO 式

<?php
// Check existence of id parameter before processing further
if(isset($_GET["id"]) && !empty(trim($_GET["id"]))){
    // Include config file
    require_once "config.php";
    
    // Prepare a select statement
    $sql = "SELECT * FROM employees WHERE id = :id";
    
    if($stmt = $pdo->prepare($sql)){
        // Bind variables to the prepared statement as parameters
        $stmt->bindParam(":id", $param_id);
        
        // Set parameters
        $param_id = trim($_GET["id"]);
        
        // Attempt to execute the prepared statement
        if($stmt->execute()){
            if($stmt->rowCount() == 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 = $stmt->fetch(PDO::FETCH_ASSOC);
                
                // Retrieve individual field value
                $name = $row["name"];
                $address = $row["address"];
                $salary = $row["salary"];
            } else{
                // URL doesn't contain valid id parameter. Redirect to error page
                header("location: error.php");
                exit();
            }
            
        } else{
            echo "Oops! Something went wrong. Please try again later.";
        }
    }
     
    // Close statement
    unset($stmt);
    
    // Close connection
    unset($pdo);
} 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>View 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">
                        <h1>View Record</h1>
                    </div>
                    <div class="form-group">
                        <label>Name</label>
                        <p class="form-control-static"><?php echo $row["name"]; ?></p>
                    </div>
                    <div class="form-group">
                        <label>Address</label>
                        <p class="form-control-static"><?php echo $row["address"]; ?></p>
                    </div>
                    <div class="form-group">
                        <label>Salary</label>
                        <p class="form-control-static"><?php echo $row["salary"]; ?></p>
                    </div>
                    <p><a href="index.php" class="btn btn-primary">Back</a></p>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

创建更新页面

同样，我们可以构建 CRUD 应用程序的 Update 功能。

让我们创建一个名为 update.php 的文件，并在其中放入以下代码。它将根据 employees 的 id 属性更新 employees 表中的现有记录。

面向过程式

<?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)){
        $name_err = "Please enter a name.";
    } elseif(!filter_var($input_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 employees SET name=?, address=?, salary=? 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
        $sql = "SELECT * FROM employees WHERE id = ?";
        if($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["address"];
                    $salary = $row["salary"];
                } 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>Salary</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>

面向对象式

<?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)){
        $name_err = "Please enter a name.";
    } elseif(!filter_var($input_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 employees SET name=?, address=?, salary=? WHERE id=?";
 
        if($stmt = $mysqli->prepare($sql)){
            // Bind variables to the prepared statement as parameters
            $stmt->bind_param("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($stmt->execute()){
                // Records updated successfully. Redirect to landing page
                header("location: index.php");
                exit();
            } else{
                echo "Something went wrong. Please try again later.";
            }
        }
         
        // Close statement
        $stmt->close();
    }
    
    // Close connection
    $mysqli->close();
} else{
    // Check existence of id parameter before processing further
    if(isset($_GET["id"]) && !empty(trim($_GET["id"]))){
        // Get URL parameter
        $id =  trim($_GET["id"]);
        
        // Prepare a select statement
        $sql = "SELECT * FROM employees WHERE id = ?";
        if($stmt = $mysqli->prepare($sql)){
            // Bind variables to the prepared statement as parameters
            $stmt->bind_param("i", $param_id);
            
            // Set parameters
            $param_id = $id;
            
            // Attempt to execute the prepared statement
            if($stmt->execute()){
                $result = $stmt->get_result();
                
                if($result->num_rows == 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 = $result->fetch_array(MYSQLI_ASSOC);
                    
                    // Retrieve individual field value
                    $name = $row["name"];
                    $address = $row["address"];
                    $salary = $row["salary"];
                } 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
        $stmt->close();
        
        // Close connection
        $mysqli->close();
    }  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>Salary</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>

PDO 式

<?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)){
        $name_err = "Please enter a name.";
    } elseif(!filter_var($input_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 employees SET name=:name, address=:address, salary=:salary WHERE id=:id";
 
        if($stmt = $pdo->prepare($sql)){
            // Bind variables to the prepared statement as parameters
            $stmt->bindParam(":name", $param_name);
            $stmt->bindParam(":address", $param_address);
            $stmt->bindParam(":salary", $param_salary);
            $stmt->bindParam(":id", $param_id);
            
            // Set parameters
            $param_name = $name;
            $param_address = $address;
            $param_salary = $salary;
            $param_id = $id;
            
            // Attempt to execute the prepared statement
            if($stmt->execute()){
                // Records updated successfully. Redirect to landing page
                header("location: index.php");
                exit();
            } else{
                echo "Something went wrong. Please try again later.";
            }
        }
         
        // Close statement
        unset($stmt);
    }
    
    // Close connection
    unset($pdo);
} else{
    // Check existence of id parameter before processing further
    if(isset($_GET["id"]) && !empty(trim($_GET["id"]))){
        // Get URL parameter
        $id =  trim($_GET["id"]);
        
        // Prepare a select statement
        $sql = "SELECT * FROM employees WHERE id = :id";
        if($stmt = $pdo->prepare($sql)){
            // Bind variables to the prepared statement as parameters
            $stmt->bindParam(":id", $param_id);
            
            // Set parameters
            $param_id = $id;
            
            // Attempt to execute the prepared statement
            if($stmt->execute()){
                if($stmt->rowCount() == 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 = $stmt->fetch(PDO::FETCH_ASSOC);
                
                    // Retrieve individual field value
                    $name = $row["name"];
                    $address = $row["address"];
                    $salary = $row["salary"];
                } 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
        unset($stmt);
        
        // Close connection
        unset($pdo);
    }  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>Salary</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>

创建删除页面

最后，我们将构建 CRUD 应用程序的 Delete 功能。

让我们创建一个名为 delete.php 的文件，并在其中放入以下代码。它将根据 employees 的 id 属性从 employees 表中删除现有记录。

面向过程式

<?php
// Process delete operation after confirmation
if(isset($_POST["id"]) && !empty($_POST["id"])){
    // Include config file
    require_once "config.php";
    
    // Prepare a delete statement
    $sql = "DELETE FROM employees WHERE 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
        $param_id = trim($_POST["id"]);
        
        // Attempt to execute the prepared statement
        if(mysqli_stmt_execute($stmt)){
            // Records deleted successfully. Redirect to landing page
            header("location: index.php");
            exit();
        } else{
            echo "Oops! Something went wrong. Please try again later.";
        }
    }
     
    // Close statement
    mysqli_stmt_close($stmt);
    
    // Close connection
    mysqli_close($link);
} else{
    // Check existence of id parameter
    if(empty(trim($_GET["id"]))){
        // 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>View 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">
                        <h1>Delete Record</h1>
                    </div>
                    <form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
                        <div class="alert alert-danger fade in">
                            <input type="hidden" name="id" value="<?php echo trim($_GET["id"]); ?>"/>
                            <p>Are you sure you want to delete this record?</p><br>
                            <p>
                                <input type="submit" value="Yes" class="btn btn-danger">
                                <a href="index.php" class="btn btn-default">No</a>
                            </p>
                        </div>
                    </form>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

面向对象式

<?php
// Process delete operation after confirmation
if(isset($_POST["id"]) && !empty($_POST["id"])){
    // Include config file
    require_once "config.php";
    
    // Prepare a delete statement
    $sql = "DELETE FROM employees WHERE id = ?";
    
    if($stmt = $mysqli->prepare($sql)){
        // Bind variables to the prepared statement as parameters
        $stmt->bind_param("i", $param_id);
        
        // Set parameters
        $param_id = trim($_POST["id"]);
        
        // Attempt to execute the prepared statement
        if($stmt->execute()){
            // Records deleted successfully. Redirect to landing page
            header("location: index.php");
            exit();
        } else{
            echo "Oops! Something went wrong. Please try again later.";
        }
    }
     
    // Close statement
    $stmt->close();
    
    // Close connection
    $mysqli->close();
} else{
    // Check existence of id parameter
    if(empty(trim($_GET["id"]))){
        // 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>View 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">
                        <h1>Delete Record</h1>
                    </div>
                    <form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
                        <div class="alert alert-danger fade in">
                            <input type="hidden" name="id" value="<?php echo trim($_GET["id"]); ?>"/>
                            <p>Are you sure you want to delete this record?</p><br>
                            <p>
                                <input type="submit" value="Yes" class="btn btn-danger">
                                <a href="index.php" class="btn btn-default">No</a>
                            </p>
                        </div>
                    </form>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

PDO 式

<?php
// Process delete operation after confirmation
if(isset($_POST["id"]) && !empty($_POST["id"])){
    // Include config file
    require_once "config.php";
    
    // Prepare a delete statement
    $sql = "DELETE FROM employees WHERE id = :id";
    
    if($stmt = $pdo->prepare($sql)){
        // Bind variables to the prepared statement as parameters
        $stmt->bindParam(":id", $param_id);
        
        // Set parameters
        $param_id = trim($_POST["id"]);
        
        // Attempt to execute the prepared statement
        if($stmt->execute()){
            // Records deleted successfully. Redirect to landing page
            header("location: index.php");
            exit();
        } else{
            echo "Oops! Something went wrong. Please try again later.";
        }
    }
     
    // Close statement
    unset($stmt);
    
    // Close connection
    unset($pdo);
} else{
    // Check existence of id parameter
    if(empty(trim($_GET["id"]))){
        // 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>View 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">
                        <h1>Delete Record</h1>
                    </div>
                    <form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
                        <div class="alert alert-danger fade in">
                            <input type="hidden" name="id" value="<?php echo trim($_GET["id"]); ?>"/>
                            <p>Are you sure you want to delete this record?</p><br>
                            <p>
                                <input type="submit" value="Yes" class="btn btn-danger">
                                <a href="index.php" class="btn btn-default">No</a>
                            </p>
                        </div>
                    </form>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

创建错误页面

最后，让我们再创建一个文件 error.php。如果请求无效，则会显示此页面，即 URL 查询字符串中缺少 id 参数或者该参数无效。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Error</title>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.css">
    <style type="text/css">
        .wrapper{
            width: 750px;
            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">
                        <h1>Invalid Request</h1>
                    </div>
                    <div class="alert alert-danger fade in">
                        <p>Sorry, you've made an invalid request. Please <a href="index.php" class="alert-link">go back</a> and try again.</p>
                    </div>
                </div>
            </div>        
        </div>
    </div>
</body>
</html>

经过漫长的旅程，我们终于用 PHP 和 MySQL 完成了我们的 CRUD 应用程序。我们建议你从一开始就查看 PHP 和 MySQL 数据库教程部分（如果你还没有介绍过），以便更好地理解本教程的每个部分。

什么是 CRUD

创建数据库表

创建配置文件

面向过程式

面向对象式

PDO 式

创建着陆页

面向过程式

面向对象式

PDO 式

创建 Create 页面

面向过程式

面向对象式

PDO 式

创建阅读页面

面向过程式

面向对象式

PDO 式

创建更新页面

面向过程式

面向对象式

PDO 式

创建删除页面

面向过程式

面向对象式

PDO 式

创建错误页面

创建 `Create` 页面