Upgrade Model CI3 to CI4

The $db property contains the connection to the database.
To work with Query Builder you need to get an instance of it.

PHP Code:

$builder = $this->db->table('table');
//or
$builder = $this->builder('table');
//or
property $table = 'table';

$builder = $this->builder();

$builder->select(...)->where(...) 


The result() method no longer exists. Use getResult().
Also orWhere, orderBy, groupStart, etc

https://codeigniter.com/user_guide/database/index.html