013.CI4框架CodeIgniter数据库操作之：查询数据库，并让数据以数组的方式返回查询结果

<?php namespace App\Models\System;

use CodeIgniter\Model;

class User_model extends Model
{
    var $Db;

    function __construct()
    {
        parent::__construct();
        //创建数据库连接
        $this->Db = \Config\Database::connect();
    }

    function getdata()
    {
        //sql语句
        $sql = "SELECT * FROM tp_user ";
        $sqlrst = $this->Db->query($sql)->getResultArray();
        return $sqlrst;
    }

}

<?php namespace App\Controllers;

class Home extends BaseController
{
    // http://127.0.0.1/CI4/public/index.php/home/showdata

    var $User_Models;

    function __construct()
    {
        //创建数据库连接
        $this->User_Models = new \App\Models\System\Login_model();
    }

    public function index()
    {
        return view(‘welcome_message‘);
    }

    public function showdata()
    {
        $rst = $this->User_Models->getdata();
        foreach ($rst as $row) {
            echo ‘编号: ‘ . $row[‘ID‘];
            echo ‘唯一值: ‘ . $row[‘MARK‘];
            echo ‘<br>‘;
        }
        echo ‘总计（条数）: ‘ . count($rst);
    }
    //--------------------------------------------------------------------

}