DB_CRUD_E-Book_Organizer

<?php
class MyClass
{
    /*
        Database Class guide:
        Sorted by CRUD order. See schema below -
        C - Insert
        R - Show
        U - Update
        D - Delete
    */

    public $db;
    function __construct($db = "ebook1")
    {
        $this->db = new mysqli("localhost", "root", "", "$db");
    }

    // CATEGORY
    public function insertCategory($name)
    {
        $m = $this->db;
        $q = "INSERT INTO categories SET cat_name='$name'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to enter new CATEGORY into database. <br/>";
        }
    }

    /* Table: AUTHORS */
    public function insertAuthor($name, $address, $email, $contacts, $fb)
    {
        $m = $this->db;
        $q = "INSERT INTO authors SET author_name='$name', address='$address', email='$email', contacts='$contacts', fb='$fb'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to enter new Author into database. <br/>";
        }
    }

    public function showAuthor_single($id)
    {
        $m = $this->db;
        $q = "SELECT * FROM authors WHERE author_id='$id'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to show 1 Author from database. <br/>";
            return;
        }

        return $r;
    }

    public function showAuthor_all()
    {
        $m = $this->db;
        $q = "SELECT * FROM authors";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to show 1 Author from database. <br/>";
            return;
        }

        return $r;
    }

    public function updateAuthor($id, $name, $address, $email, $contacts, $fb)
    {
        $m = $this->db;
        $q = "UPDATE authors SET author_name='$name', address='$address', email='$email', contacts='$contacts', fb='$fb' WHERE author_id='$id'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to update 1 Author from database. <br/>";
        }
    }

    public function deleteAuthor($id)
    {
        $m = $this->db;
        $q = "DELETE * FROM authors WHERE author_id='$id'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to delete 1 Author from database. <br/>";
        }
    }

    /* TABLE: publisher */
    public function insertPublisher($name, $address, $email, $contacts, $fb)
    {
        $m = $this->db;
        $q = "INSERT INTO publisher SET pub_name='$name', address='$address', email='$email', contacts='$contacts', fb='$fb'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to enter new Publisher into database. <br/>";
        }
    }

    public function showPublisher_single($id)
    {
        $m = $this->db;
        $q = "SELECT * FROM publisher WHERE pub_id='$id'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to show 1 Publisher from database. <br/>";
            return;
        }

        return $r;
    }

    public function showPublisher_all()
    {
        $m = $this->db;
        $q = "SELECT * FROM publisher";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to show 1 Publisher from database. <br/>";
            return;
        }

        return $r;
    }

    public function updatePublisher($name, $address, $email, $contacts, $fb)
    {
        $m = $this->db;
        $q = "UPDATE publisher SET pub_name='$name', address='$address', email='$email', contacts='$contacts', fb='$fb'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to update 1 Publisher from database. <br/>";
        }
    }

    public function deletePublisher($id)
    {
        $m = $this->db;
        $q = "DELETE * FROM publisher WHERE pub_id='$id'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to delete 1 Publisher from database. <br/>";
        }
    }

    /* TABLE: items */
    public function insertItem($name, $cat_id, $description, $rating, $release)
    {
        $m = $this->db;
        $q = "INSERT INTO items SET item_name='$name', cat_id='$cat_id', description='$description', rating='$rating', release_yr='$release'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to enter new Item into database. <br/>";
        }
    }

    public function showItem_single($id)
    {
        $m = $this->db;
        $q = "SELECT * FROM items WHERE item_id='$id'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to show 1 Item from database. <br/>";
            return;
        }

        return $r;
    }

    public function showItems_all()
    {
        $m = $this->db;
        $q = "SELECT * FROM items";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to show items from database. <br/>";
            return;
        }

        return $r;
    }

    public function updateItem($id, $name, $cat_id, $description, $rating, $release)
    {
        $m = $this->db;
        $q = "UPDATE items SET item_name='$name', cat_id='$cat_id', description='$description', rating='$rating', release='$release' WHERE item_id='$id'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to delete 1 item from database. <br/>";
        }
    }

    public function deleteItem($id)
    {
        $m = $this->db;
        $q = "DELETE * FROM items WHERE item_id='$id'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to delete 1 Author from database. <br/>";
        }
    }

    /* TABLE: items_authors */ /* ===================== PROBLEM WITH THIS TABLE ========================================= */
    public function insertItemAuthors($slno, $item_id, $auth_id, $item_sl)
    {
        $m = $this->db;
        $q = "INSERT INTO items_authors SET slno='$slno', item_id='$item_id', auth_id='$auth_id', item_sl='$item_sl'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to enter new Item into database. <br/>";
        }
    }

    public function showItemAuthor_single($id)
    {
        $m = $this->db;
        $q = "SELECT * FROM items_authors WHERE item_id='$id'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to show 1 Item from database. <br/>";
            return;
        }

        return $r;
    }

    public function showItemAuthors_all()
    {
        $m = $this->db;
        $q = "SELECT * FROM items_authors";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to show items from database. <br/>";
            return;
        }

        return $r;
    }

    public function updateItemAuthors($slno, $item_id, $auth_id, $item_sl)
    {
        $m = $this->db;
        $q = "UPDATE authors SET slno='$slno', item_id='$item_id', auth_id='$auth_id', item_sl='$item_sl' WHERE slno='$slno'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to update 1 item from database. <br/>";
        }
    }

    public function deleteItemAuthors($slno)
    {
        $m = $this->db;
        $q = "DELETE * FROM authors WHERE slno='$slno'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to delete 1 Author from database. <br/>";
        }
    }

    /* TABLE: item_publishers */
    public function insertItemPublisher($slno, $item_id, $pub_id, $item_sl)
    {
        $m = $this->db;
        $q = "INSERT INTO item_publishers SET slno='$slno', item_id='$item_id', pub_id='$pub_id', item_sl='$item_sl'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to enter new Item Publisher into database. <br/>";
        }
    }

    public function showItemPublisher_single($slno)
    {
        $m = $this->db;
        $q = "SELECT * FROM item_publishers WHERE slno='$slno'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to show 1 Item Publisher from database. <br/>";
            return;
        }

        return $r;
    }

    public function showItemPublishers_all()
    {
        $m = $this->db;
        $q = "SELECT * FROM item_publishers";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to show Item Publisher from database. <br/>";
            return;
        }

        return $r;
    }

    public function updateItemPublishers($slno, $item_id, $pub_id, $item_sl)
    {
        $m = $this->db;
        $q = "UPDATE item_publishers SET slno='$slno', item_id='$item_id', pub_id='$pub_id', item_sl='$item_sl'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to update 1 Item Publisher in database. <br/>";
        }
    }

    public function deleteItemPublishers($slno)
    {
        $m = $this->db;
        $q = "DELETE * FROM item_publishers WHERE slno='$slno'";
        $r = $m->query($q);

        if (!$r) {
            echo "An error occured while trying to delete 1 Author from database. <br/>";
        }
    }
    // 1.5 hrs
}
?>