Question

Should I be using the __construct option to create a new record? Below is the class I have called ‘Course’. I will only actually be “creating” a course 25% of the time, the rest of the time I’ll want to lookup courses and what not.

class Course {
    private $db;

    function __construct($db, $data) {
        global $error, $mysqli;

        $this->db = $db;

        requireOrError($data['course_type_id'], "Course Type Required");
        requireOrError($data['instructor_id'], "Instructor Required");
        requireOrError($data['dz_name'], "DZ Name Required");
        requireOrError($data['dz_address'], "DZ Address Required");
        requireOrError($data['dz_city'], "DZ City Required");
        requireOrError($data['dz_state'], "DZ State Required");
        requireOrError($data['dz_zip'], "DZ Zip Required");
        requireOrError($data['dz_email'], "DZ Email Required");     
        requireOrError($data['start_date'], "Course Start Date Required");
        requireOrError($data['end_date'], "Course End Date Required");
        requireOrError($data['student_slots'], "Number Of Student Slots Required");

        if(! is_numeric($data['student_slots'])) {
            $error[] = "Invalid Student Slots - Must be a number";
        }

        setError($error);

        if(empty($error)) {
            $add = $mysqli->query("INSERT INTO " . $this->db['courses'] . " (course_type_id, instructor_id, dz_name, dz_address, dz_city, dz_state, dz_zip, dz_email, start_date, end_date, student_slots, notes) VALUES ('$data[course_type_id]', '$data[instructor_id]', '$data[dz_name]', '$data[dz_address]', '$data[dz_city]', '$data[dz_state]', '$data[dz_zip]', '$data[dz_email]', '$data[start_date]', '$data[end_date]', '$data[student_slots]', '$data[notes]')");
            redirectTo("instructors.php");
        }
    }
}

I was going to create a function called “getCourseInfo” where I could pass an ID and it’ll return the course object. Is this the best way to do it, or, should I change the __construct behavior to create. Also, could you give me an example of how I would create/lookup?

Thanks!

Answer 1

No. You should have a separate method to create a record that you either pass the parameters as function arguments, or as an array. For example:

<?php
class Course {

    protected $db;    

    public function __construct($db) {
        $this->db = $db;
    }

    public function fetchById($id) {
        // perform database query; look-up on ID
    }

    public function create($data) {
        // validate your $data
        // create your record
        // return either boolean true or the ID of the newly-created record
        // and errors, either return boolean false or throw an exception
    }
}

You can then use your class as follows:

<?php

// create PDO instance in $pdo variable

$course = new Course($pdo);

$data = array(
    'course_type_id' => $_POST['course_type_id'],
    'instructor_id'  => $_POST['instructor_id'],
    // and so on...
);

if ($course->create($data)) {
    echo 'Course created.';
}
else {
    echo 'Error creating course.';
}

Make sure to escape and sanitize any posted data.