新手求助：将指定PHP代码转换为CodeIgniter代码

Hey there! Since you're new to CodeIgniter, let's walk through converting your raw PHP database query into CodeIgniter's cleaner, safer approach using its built-in Database Class. First, let's break down what your original code does: it fetches id_matpel values from the matpel table, sorts them by bobot descending then nama_matpel ascending, stores them in an array, and loops through that array.

Step 1: Use CodeIgniter's Model (Best Practice) #

CodeIgniter encourages separating database logic into models for better maintainability. Here's how to create a model for your query:

<?php
class Matpel_model extends CI_Model {
    public function get_matpel_ids() {
        // Note: Your original SQL has a redundant `WHERE id_matpel` clause (no condition)
        // I've kept it out here since it doesn't filter any rows—double-check if you meant to add a condition!
        
        // Build the query using CodeIgniter's query builder
        $this->db->select('id_matpel');
        $this->db->from('matpel');
        $this->db->order_by('bobot', 'DESC');
        $this->db->order_by('nama_matpel', 'ASC');
        
        $query = $this->db->get();
        
        // Check if we have results
        if ($query->num_rows() > 0) {
            // Option 1: Return a 2D array (each item is ['id_matpel' => 'value'])
            return $query->result_array();
            
            // Option 2: Return a 1D array of just the ids (simpler for your loop)
            // return array_column($query->result_array(), 'id_matpel');
        }
        
        // Return empty array if no results
        return [];
    }
}

Step 2: Call the Model from Your Controller #

Next, load the model in your controller and use it to get the data, then loop through it:

<?php
class Your_Controller extends CI_Controller {
    public function your_method() {
        // Load the model first
        $this->load->model('Matpel_model');
        
        // Get the array of matpel ids
        $arraymatpel1 = $this->Matpel_model->get_matpel_ids();
        
        // Loop through the array (adjust based on which option you used in the model)
        // If using Option 1 (2D array):
        foreach ($arraymatpel1 as $keymatpel => $value) {
            $matpelid = $value['id_matpel'];
            // Add your logic here for each $matpelid
        }
        
        // If using Option 2 (1D array), the loop is simpler:
        // foreach ($arraymatpel1 as $matpelid) {
        //     // Add your logic here for each $matpelid
        // }
    }
}

Key Notes for New CodeIgniter Users: #

• No Manual Database Connections: CodeIgniter handles database connections automatically once you configure your database settings in application/config/database.php.
• Query Builder Safety: The query builder helps prevent SQL injection (especially if you add dynamic conditions later—use $this->db->where() with parameter binding).
• Redundant WHERE Clause: Your original SQL had WHERE id_matpel with no condition—this doesn't filter any rows, so I omitted it. If you intended to add a condition (like WHERE id_matpel = ?), feel free to adjust the code accordingly!

内容的提问来源于stack exchange，提问作者241196