直接上代码吧，有时间在维护下

class DB {

private $host; //主机

private $username; //用户名

private $password; //密码

private $dbName; //数据库名称

private $port; //数据库端口

private $socket; //套接字

private $mysqli; //mysqli对象

private $charset; //字符集

private $lastSql; //最后执行的sql

public function __construct($array=[])

{

$this->charset = isset($array['charset']) ? $array['charset'] : 'utf8';

$this->connect($array);

$this->mysqlConnect();

}

public function connect($array=[])

{

$this->host = isset($array['host']) ? $array['host'] : '127.0.0.1';

$this->username = isset($array['username']) ? $array['username'] : 'root';

$this->password = isset($array['password']) ? $array['password'] : 'root';

$this->dbName = isset($array['dbName']) ? $array['dbName'] : '';

$this->port = isset($array['port']) ? $array['port'] : 3306;

$this->socket = isset($array['socket']) ? $array['socket'] : '';

}

private function mysqlConnect()

{

$this->mysqli = new mysqli($this->host,$this->username,$this->password,$this->dbName,$this->port);

}

public function query($sql)

{

$this->lastSql = $sql;

$result = $this->mysqli->query($this->lastSql);

if($result === false) {

$this->error();

}

return $result;

}

public function Charset($charset='')

{

$this->charset = $charset ? $charset: $this->charset;

$this->execute("set names {$this->charset}");

}

public function execute($sql)

{

$this->query($sql);

return true;

}

public function select($sql)

{

$result = $this->query($sql);

return $result->fetch_all(MYSQLI_ASSOC);

}

public function getLastSql()

{

return $this->lastSql;

}

public function error()

{

$result = '';

if($this->mysqli->error) {

$result.= "错误提示：{$this->mysqli->error}

";

}

if($this->mysqli->errno) {

$result.= "错误代号：{$this->mysqli->errno}

";

}

if(!empty($result)){

$result.="错误的sql语句:{$this->lastSql}";

}

if(!empty($result)) {

exit($result);

} else {

exit('没有错误');

}

}

}

本地试试：

$db = new DB(['dbName'=>'test']);

var_dump($db->select('select * from test limit 0,5'));

var_dump($db->select('select name,time from test where id in(1,5)'));

echo $db->getLastSql();

运行结果如图所示：