实例
<?php class Query { private $sql=[]; private $pdo=null; public function __construct() { $this->pdo=new PDO('mysql:host=127.0.0.1;dbname=php','root','root'); } public function table($table) { $this->sql['table']=$table; return $this; } public function fields($fields) { $this->sql['fields']=$fields; return $this; } public function where($where) { $this->sql['where'] = $where; return $this; } public function select() { $sql = "SELECT {$this->sql['fields']} FROM {$this->sql['table']} WHERE {$this->sql['where']}"; $stmt = $this->pdo->prepare($sql); $stmt->execute(); return $stmt->fetchAll(PDO::FETCH_ASSOC); } }
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实例
<?php require 'Query1.php'; class Db { public static function __callStatic($name,$arguments) { return call_user_func_array([(new Query()),$name],$arguments); } } $result = Db::table('user')->fields('id,name,email')->where('id > 1')->select(); //print_r($result); // 用表格将查询结果格式化输出 $table = '<table border="1" cellpadding="5" cellspacing="0" width="60%" align="center">'; $table .= '<caption style="font-size: 1.5rem;margin:15px;">用户信息表</caption>'; $table .= '<tr bgcolor="#90ee90"><th>ID</th><th>姓名</th><th>邮箱</th></tr>'; foreach ($result as $user) { $table .= '<tr align="center">'; $table .= '<td>'.$user['id'].'</td>'; $table .= '<td>'.$user['name'].'</td>'; $table .= '<td>'.$user['email'].'</td>'; $table .= '</tr>'; } $table .= '</table>'; $num = '<p style="text-align: center"> 共计: <span style="color:red">'.count($result).'</span>条记录</p>'; echo $table, $num;
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问答: 后期静态绑定的原理与使用场景分析
原理:子类调用父类同名方法并在子类进行了重写,通过static进行静态绑定,始终指向静态方法的调用者。
使用场景分析:当子类需要对父类同名方法重写并调用的情况。