Make Products Persistent

From the class Tx_Inventory_Domain_Model_Product, now we already can generate instances – therefore concrete products with individual properties – at script run time. These are available however only in volatile form in the memory and are deleted by PHP after the page was produced completely by TYPO3. So that the products are available over a longer time, we must make it “durable”. Usually this happens in that they are stored into a database. Therefore first of all we create the database table necessary for that.

Tip

The creating of the database tables can be done by the Kickstarter. In TYPO3 V5, these steps are completely omitted.

TYPO3 will do this for us if we register the corresponding SQL command in the file EXT:inventory/ext_tables.sql:

CREATE TABLE tx_inventory_domain_model_product (
            uid int(11) unsigned DEFAULT '0' NOT NULL auto_increment,
            pid int(11) DEFAULT '0' NOT NULL,

            name varchar(255) DEFAULT '' NOT NULL,
            description text NOT NULL,
            quantity int(11) DEFAULT '0' NOT NULL,

            PRIMARY KEY (uid),
            KEY parent (pid),
    );

This SQL command designs a new table with the corresponding columns. The columns uid and pid serve to the internal administration. Our product characteristics name, description and quantity appear as columns again.

The entries in the database are accessed by the Backend of TYPO3. The forms of the Backend are produced on the basis of a configuration, that is stored in a PHP array, the so-called Table-Configuration-Array (shortly TCA).

Within the Extension we can access the data transparently by the repositories. “Transparently” means that we don’t have to thought about the type of the storage of the data when accessing the repositories.

So that the Backend now, how it should show the product data in a form, we must configure this for the table in the file EXT:inventory/ext_tables.php. This is stored in the Array $TCA under the table name as a key in the configuration. This comprises several sections. In the section ctrl, basic characteristics are how the table name or the statement which table column the label is supposed to be taken for the entries. In the section columns is described for each table column how this in that is supposed to be shown in the Backend. The section type defines, in which sequence the table columns are indicated, and like this where appropriate arranged.

Tip

The possibilities to impact the TCA the edition in that Backend, are immense. In the frame these beeches we only can tear this. You find a fully permanent listing of all option online at http://typo3.org/documentation/document-library/core-documentation/doc_core_api/4.3.0/view/4/1/. In more extensive Extensions, one would evacuate the sections columns and type out of performance reasons also into an own file tca.php. In our example, this minimal configuration should suffice however.

<?php
if (!defined ('TYPO3_MODE')) die ('Access denied.');

$TCA['tx_inventory_domain_model_product'] = array (
'ctrl' => array (
        'title' => 'Inventory',
        'label' => 'name',
),
'columns' => array(
        'name' => array(
        'label' => 'Item Label',
                'config' => array(
                        'type' => 'input',
                        'size' => '20',
                        'eval' => 'trim,required'
                )
        ),
        'description' => array(
                'label' => 'Item Description',
                'config' => array(
                        'type' => 'text',
                        'eval' => 'trim'
                )
        ),
        'quantity' => array(
                'label' => 'Stock Quantity',
                'config' => array(
                        'type' => 'input',
                        'size' => '4',
                        'eval'=> 'int'
                )
        ),
),
'types' => array(
        '0' => array('showitem' => 'name, description, quantity')
)
);
?>

After we installed the Extension, we can create our first products in the backend. Like shown in image 4-2, we create a sys folder that takes the products (see 1 in figure 4-2). In this, we put some few new inventory data (see 2 in figure 4-2).

Figure 4-2: Create a new product

In this section we create a copy (or a model) of the reality, as we transferred only a part of the properties of the real products in software, that play a role in our domain. This model, which is abstracted of the real world, is completely designed with this.

In order to access the objects created in the backend, we create a Repository for the products. The Tx_Inventory_Domain_Repository_ProductRepository is an object, in that the products are discarded. We can request a Repository to find all (or certain) products and deliver it to us. The Repository class is very short in our case:

<?php
class Tx_Inventory_Domain_Repository_ProductRepository
extends Tx_Extbase_Persistence_Repository {}
?>

Our ProductRepository must be derived by Tx_Extbase_Persistence_Repository and inherits by this all methods. It can remain empty therefore in our simple example. We put the class file ProductRepository.php into the directory EXT:inventory/Classes/Domain/Repository/.