本文实例讲述了PHP封装类似thinkphp连贯操作数据库Db类与简单应用。分享给大家供大家参考，具体如下：

<?phpheader("Content-Type:text/html;charset=utf-8");/** *php操作mysql的工具类 */class Db{ private $_db = null;//数据库连接句柄 private $_table = null;//表名 private $_where = null;//where条件 private $_order = null;//order排序 private $_limit = null;//limit限定查询 private $_group = null;//group分组 private $_configs = array( 'hostname' => 'localhost', 'dbname' => 'test', 'username' => 'root', 'password' => '1234' );//数据库配置 /** * 构造函数，连接数据库 */ public function __construct(){ $link = $this->_db; if(!$link){ $db = mysqli_connect($this->_configs['hostname'],$this->_configs['username'],$this->_configs['password'],$this->_configs['dbname']); mysqli_query($db,"set names utf8"); if(!$db){ $this->ShowException("错误信息".mysqli_connect_error()); } $this->_db = $db; } } /** * 获取所有数据 * * @param <type> $table The table * * @return boolean All. */ public function getAll($table=null){ $link = $this->_db; if(!$link)return false; $sql = "SELECT * FROM {$table}"; $data = mysqli_fetch_all($this->execute($sql)); return $data; } public function table($table){ $this->_table = $table; return $this; } /** * 实现查询操作 * * @param string $fields The fields * * @return boolean ( description_of_the_return_value ) */ public function select($fields="*"){ $fieldsStr = ''; $link = $this->_db; if(!$link)return false; if(is_array($fields)){ $fieldsStr = implode(',', $fields); }elseif(is_string($fields)&&!empty($fields)){ $fieldsStr = $fields; } $sql = "SELECT {$fields} FROM {$this->_table} {$this->_where} {$this->_order} {$this->_limit}"; $data = mysqli_fetch_all($this->execute($sql)); return $data; } /** * order排序 * * @param string $order The order * * @return boolean ( description_of_the_return_value ) */ public function order($order=''){ $orderStr = ''; $link = $this->_db; if(!$link)return false; if(is_string($order)&&!empty($order)){ $orderStr = "ORDER BY ".$order; } $this->_order = $orderStr; return $this; } /** * where条件 * * @param string $where The where * * @return <type> ( description_of_the_return_value ) */ public function where($where=''){ $whereStr = ''; $link = $this->_db; if(!$link)return $link; if(is_array($where)){ foreach ($where as $key => $value) { if($value == end($where)){ $whereStr .= "`".$key."` = '".$value."'"; }else{ $whereStr .= "`".$key."` = '".$value."' AND "; } } $whereStr = "WHERE ".$whereStr; }elseif(is_string($where)&&!empty($where)){ $whereStr = "WHERE ".$where; } $this->_where = $whereStr; return $this; } /** * group分组 * * @param string $group The group * * @return boolean ( description_of_the_return_value ) */ public function group($group=''){ $groupStr = ''; $link = $this->_db; if(!$link)return false; if(is_array($group)){ $groupStr = "GROUP BY ".implode(',',$group); }elseif(is_string($group)&&!empty($group)){ $groupStr = "GROUP BY ".$group; } $this->_group = $groupStr; return $this; } /** * limit限定查询 * * @param string $limit The limit * * @return <type> ( description_of_the_return_value ) */ public function limit($limit=''){ $limitStr = ''; $link = $this->_db; if(!$link)return $link; if(is_string($limit)||!empty($limit)){ $limitStr = "LIMIT ".$limit; }elseif(is_numeric($limit)){ $limitStr = "LIMIT ".$limit; } $this->_limit = $limitStr; return $this; } /** * 执行sql语句 * * @param <type> $sql The sql * * @return boolean ( description_of_the_return_value ) */ public function execute($sql=null){ $link = $this->_db; if(!$link)return false; $res = mysqli_query($this->_db,$sql); if(!$res){ $errors = mysqli_error_list($this->_db); $this->ShowException("报错啦！<br/>错误号：".$errors[0]['errno']."<br/>SQL错误状态：".$errors[0]['sqlstate']."<br/>错误信息：".$errors[0]['error']); die(); } return $res; } /** * 插入数据 * * @param <type> $data The data * * @return boolean ( description_of_the_return_value ) */ public function insert($data){ $link = $this->_db; if(!$link)return false; if(is_array($data)){ $keys = ''; $values = ''; foreach ($data as $key => $value) { $keys .= "`".$key."`,"; $values .= "'".$value."',"; } $keys = rtrim($keys,','); $values = rtrim($values,','); } $sql = "INSERT INTO `{$this->_table}`({$keys}) VALUES({$values})"; mysqli_query($this->_db,$sql); $insertId = mysqli_insert_id($this->_db); return $insertId; } /** * 更新数据 * * @param <type> $data The data * * @return <type> ( description_of_the_return_value ) */ public function update($data){ $link = $this->_db; if(!$link)return $link; if(is_array($data)){ $dataStr = ''; foreach ($data as $key => $value) { $dataStr .= "`".$key."`='".$value."',"; } $dataStr = rtrim($dataStr,','); } $sql = "UPDATE `{$this->_table}` SET {$dataStr} {$this->_where} {$this->_order} {$this->_limit}"; $res = $this->execute($sql); return $res; } /** * 删除数据 * * @return <type> ( description_of_the_return_value ) */ public function delete(){ $link = $this->_db; if(!$link)return $link; $sql = "DELETE FROM `{$this->_table}` {$this->_where}"; $res = $this->execute($sql); return $res; } /** * 异常信息输出 * * @param <type> $var The variable */ private function ShowException($var){ if(is_bool($var)){ var_dump($var); }else if(is_null($var)){ var_dump(NULL); }else{ echo "<pre style='position:relative;z-index:1000;padding:10px;border-radius:5px;background:#F5F5F5;border:1px solid #aaa;font-size:14px;line-height:18px;opacity:0.9;'>".print_r($var,true)."</pre>"; } }}$db = new Db();//查询操作var_dump($db->table('user')->where('id > 2')->order('id desc')->limit('2,4')->select());//插入操作var_dump($db->table('user')->insert(array('username'=>'user','password'=>'pwd')));//更新操作var_dump($db->table('user')->where('id = 1')->update(array('username'=>'user1','password'=>'pwd1')));//删除操作var_dump($db->table('user')->where('id = 1')->delete());

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