Cursor rule

1---
2description: 
3globs: 
4alwaysApply: false
5---
6# Moodle Database Patterns
7 
8## Purpose
9Ensure consistent and efficient database interactions using Moodle's database abstraction layer.
10 
11## Instructions
12When working with databases in Moodle PHP code, follow these patterns:
13 
141. **Use Moodle's Database API**: Always use `$DB` global object, never direct MySQL functions
152. **Parameterized Queries**: Use `$DB->get_records_sql()` with parameters for complex queries
163. **Simple Queries**: Use `$DB->get_records()`, `$DB->get_record()`, `$DB->insert_record()`, etc.
174. **Transactions**: Use `$DB->transaction_start()` and `$DB->transaction_commit()` for multi-table operations
185. **Error Handling**: Always check return values and use `$DB->get_last_error()` for debugging
196. **Performance**: Use `$DB->set_debug()` sparingly, prefer logging for production
207. **Table Prefix**: Never hardcode table names, use `$CFG->prefix` if needed
218. **Record Objects**: Return stdClass objects, not arrays for consistency
22 
23## Examples
24 
25```php
26<?php
27// File: ./includes/database_example.php
28 
29/**
30 * Example of proper database usage in Moodle
31 */
32function get_user_courses($userid) {
33    global $DB;
34    
35    // Simple query with conditions
36    $courses = $DB->get_records('enrol', ['userid' => $userid], 'timecreated DESC');
37    
38    // Complex query with parameters
39    $sql = "SELECT c.*, e.timecreated 
40            FROM {course} c 
41            JOIN {enrol} e ON c.id = e.courseid 
42            WHERE e.userid = :userid 
43            AND e.status = :status";
44    
45    $params = [
46        'userid' => $userid,
47        'status' => ENROL_USER_ACTIVE
48    ];
49    
50    $courses = $DB->get_records_sql($sql, $params);
51    
52    // Transaction example
53    $transaction = $DB->start_delegated_transaction();
54    try {
55        $DB->insert_record('user_log', [
56            'userid' => $userid,
57            'action' => 'course_access',
58            'time' => time()
59        ]);
60        
61        $DB->update_record('user', [
62            'id' => $userid,
63            'lastaccess' => time()
64        ]);
65        
66        $transaction->allow_commit();
67    } catch (Exception $e) {
68        $transaction->rollback($e);
69        throw $e;
70    }
71    
72    return $courses;
73}
74```
75 
76## Exceptions
77- Direct SQL may be needed for complex reporting queries
78- Third-party plugins may use different database patterns
79