The above example is wrong, it will not detect a failed query.
The easiest way to reproduce a failed query is, for instance, a foreign key constraint on the table you are trying to delete from.
SQL:
Code:
CREATE TABLE `blogpost` (
`id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`content` text,
PRIMARY KEY (`id`)
);
INSERT INTO blogpost SET content = 'this is my first blogpost';
CREATE TABLE `comment` (
`id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`blogpost_id` bigint(20) unsigned DEFAULT NULL,
`comment` text,
PRIMARY KEY (`id`),
KEY `comment_fk_blogpost_id` (`blogpost_id`),
CONSTRAINT `comment_fk_blogpost_id` FOREIGN KEY (`blogpost_id`) REFERENCES `blogpost` (`id`) ON UPDATE CASCADE
);
INSERT INTO comment SET blogpost_id = 1, comment = 'Wow great! Welcome to the blogger community!';
Doing a delete query on the above blogpost table row will result in SQL error:
Code:
MariaDB [blog]> SELECT * FROM blogpost;
+----+---------------------------+
| id | content |
+----+---------------------------+
| 1 | this is my first blogpost |
+----+---------------------------+
1 row in set (0.00 sec)
MariaDB [blog]> SELECT * FROM comment;
+----+-------------+----------------------------------------------+
| id | blogpost_id | comment |
+----+-------------+----------------------------------------------+
| 1 | 1 | Wow great! Welcome to the blogger community! |
+----+-------------+----------------------------------------------+
1 row in set (0.00 sec)
MariaDB [blog]> DELETE FROM blogpost WHERE id = 1;
ERROR 1451 (23000): Cannot delete or update a parent row: a foreign key constraint fails (`blog`.`comment`, CONSTRAINT `comment_fk_blogpost_id` FOREIGN KEY (`blogpost_id`) REFERENCES `blogpost` (`id`) ON UPDATE CASCADE)
Now let's see what happens in CI4.
Controller code:
PHP Code:
<?php
namespace App\Controllers;
use CodeIgniter\Controller;
class BlogPostController extends Controller
{
public function delete(int $id)
{
$model = new BlogPostModel();
try {
if ($result = $model->delete($id)) {
print "success\n";
print "... or is it?\n";
print_r($result);
} else {
print "ooops\n";
}
} catch (\Exception $e) {
print "Caught exception: " . $e->getMessage() . "\n";
}
}
}
And the result:
Code:
dev@bloghost:~/public$ php index.php blogpost/1/delete
success
... or is it?
CodeIgniter\Database\MySQLi\Result Object
(
[connID] => mysqli Object
(
[affected_rows] => -1
[client_info] => mysqlnd 5.0.12-dev - 20150407 - $Id: ************************* $
[client_version] => 50012
[connect_errno] => 0
[connect_error] =>
[errno] => 1451
[error] => Cannot delete or update a parent row: a foreign key constraint fails (`blog`.`comment`, CONSTRAINT `comment_fk_blogpost_id` FOREIGN KEY (`blogpost_id`) REFERENCES `blogpost` (`id`) ON UPDATE CASCADE)
[error_list] => Array
(...)
