ThinkPHP中的CURD操作

<?php
    //查询多条记录,返回二维数组
    $result = M("admin")->select();
    $result = M("admin")->where("id>2")->select();
    $result = M("admin")->where("id>2")->order("id desc")->limit("0,5")->field("id,username,psssword")->select();
    $result = M("admin")->where("id>2")->group("messageId")->having("messageId > 3")->order("id desc")->limit("0,5")->field("id,username,psssword")->select();
    //查询一条记录，返回一维数组
    $result = M("admin")->find();
    $result = M("admin")->where("id=2")->find();

    //要处理的数据放在数组data中
    $data   = array(
            "username" => ‘wang‘,
            "password" => "123456"
        );
    //添加记录，返回影响行数
    $updateRowNum = M("admin")->add($data);
    //删除记录，返回影响行数
    $updateRowNum = M("admin")->where("id = 2")->delete();
    //修改数据放在新数组new_data中
    $new_data   = array(
            "username" => ‘wang_new‘,
            "password" => "123456_new"
        );
    //修改记录，返回影响行数
    $updateRowNum = M("admin")->where("id = 2")->save($new_data);
    
    //执行select语句(不管是多行还是一行，全部返回二维数组)
    $result = M()->query("select * from admin a,user u where a.id = user.aid");
    //执行insert、update、delete语句，返回受影响行数
    $updateRowNum = M()->execute("insert/update/delete语句");
    //计算查询行数(一般用于select语句)
    $row    = M("admin")->select()->count();
    $row    = M("admin")->where("id > 3")->select()->count();
?>