Difference between revisions of "Developing a MVC Component/Using the database"
From Joomla! Documentation
< Archived:Developing a MVC Component
Line 18: | Line 18: | ||
CREATE TABLE `#__helloworld` ( | CREATE TABLE `#__helloworld` ( | ||
− | + | `id` int(11) NOT NULL auto_increment, | |
− | + | `greeting` varchar(25) NOT NULL, | |
− | + | PRIMARY KEY (`id`) | |
) ENGINE=MyISAM AUTO_INCREMENT=0 DEFAULT CHARSET=utf8; | ) ENGINE=MyISAM AUTO_INCREMENT=0 DEFAULT CHARSET=utf8; | ||
Revision as of 19:09, 21 November 2010
This page has been archived. This page contains information for an unsupported Joomla! version or is no longer relevant. It exists only as a historical reference, it will not be improved and its content may be incomplete and/or contain broken links.
Articles in this series[edit]
Articles in this Series
- Introduction
- Developing a Basic Component
- Adding a view to the site part
- Adding a menu type to the site part
- Adding a model to the site part
- Adding a variable request in the menu type
- Using the database
- Basic backend
- Adding language management
- Adding backend actions
- Adding decorations to the backend
- Adding verifications
- Adding categories
- Adding configuration
- Adding ACL
- Adding an install/uninstall/update script file
- Using the language filter facility
- Adding an update server
- Example of a Frontend Update Function
- Example of Menu Parameters & Stylesheets
Introduction[edit]
This tutorial is part of the Developing a Model-View-Controller (MVC) Component for Joomla!1.6 tutorial. You are encouraged to read the previous parts of the tutorial before reading this.
Using the database[edit]
Components usually manage their contents using the database. During the install/uninstall/update phase of a component, you can execute SQL queries through the use of SQL text files.
With your favorite file manager and editor put a file admin/sql/install.mysql.utf8.sql containing:
admin/sql/install.mysql.utf8.sql
DROP TABLE IF EXISTS `#__helloworld`;
CREATE TABLE `#__helloworld` (
`id` int(11) NOT NULL auto_increment,
`greeting` varchar(25) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=0 DEFAULT CHARSET=utf8;
INSERT INTO `#__helloworld` (`greeting`) VALUES
('Hello World!'),
('Good bye World!');
This is the install file. It will be executed if your put an appropriate order in the helloworld.xml file
helloworld.xml
<?xml version="1.0" encoding="utf-8"?>
<extension type="component" version="1.6.0" method="upgrade">
<name>Hello World!</name>
<creationDate>November 2009</creationDate>
<author>John Doe</author>
<authorEmail>john.doe@example.org</authorEmail>
<authorUrl>http://www.example.org</authorUrl>
<copyright>Copyright Info</copyright>
<license>License Info</license>
<version>0.0.6</version>
<description>Description of the Hello World component ...</description>
<install> <!-- Runs on install -->
<sql>
<file driver="mysql" charset="utf8">sql/install.mysql.utf8.sql</file>
</sql>
</install>
<uninstall> <!-- Runs on uninstall -->
<sql>
<file driver="mysql" charset="utf8">sql/uninstall.mysql.utf8.sql</file>
</sql>
</uninstall>
<files folder="site">
<filename>index.html</filename>
<filename>helloworld.php</filename>
<filename>controller.php</filename>
<folder>views</folder>
<folder>models</folder>
</files>
<administration>
<menu>Hello World!</menu>
<files folder="admin">
<filename>index.html</filename>
<filename>helloworld.php</filename>
<!-- SQL files section -->
<folder>sql</folder>
<!-- tables files section -->
<folder>tables</folder>
<!-- models files section -->
<folder>models</folder>
</files>
</administration>
</extension>
Do the same for the uninstall file:
With your favorite file manager and editor put a file admin/sql/uninstall.mysql.utf8.sql containing:
admin/sql/uninstall.mysql.utf8.sql
DROP TABLE IF EXISTS `#__helloworld`;
And finally, create a folder for storing updates in the future admin/sql/updates/mysql
Adding a new field type[edit]
For the moment, we have used a hard coded field type for messages. We need to use our database for choosing the message.
Modify the site/views/helloworld/tmpl/default.xml file and put these lines
site/views/helloworld/tmpl/default.xml
<?xml version="1.0" encoding="utf-8"?>
<!-- $Id: default.xml 37 2010-11-19 15:01:11Z chdemko $ -->
<metadata>
<layout title="COM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_TITLE">
<message>COM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_DESC</message>
</layout>
<fields
name="request"
addfieldpath="/administrator/components/com_helloworld/models/fields"
>
<fieldset name="request">
<field
name="id"
type="helloworld"
label="COM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_MSG_LABEL"
description="COM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_MSG_DESC"
/>
</fieldset>
</fields>
</metadata>
It introduces a new field type and tells Joomla to look for the field definition in the /administrator/components/com_helloworld/models/fields folder.
With your favorite file manager and editor put a file admin/models/fields/helloworld.php file containing:
admin/models/fields/helloworld.php
<?php
// No direct access to this file
defined('_JEXEC') or die;
// import the list field type
jimport('joomla.html.html.list');
/**
* HelloWorld Form Field class for the HelloWorld component
*/
class JFormFieldHelloWorld extends JFormFieldList
{
/**
* The field type.
*
* @var string
*/
protected $type = 'HelloWorld';
/**
* Method to get a list of options for a list input.
*
* @return array An array of JHtml options.
*/
protected function getOptions()
{
$db = JFactory::getDBO();
$query = $db->getQuery(true);
$query->select('id,greeting');
$query->from('#__helloworld');
$db->setQuery($query);
$messages = $db->loadObjectList();
$options = array();
foreach($messages as $message)
{
$options[] = JHtml::_('select.option', $message->id, $message->greeting);
}
$options = array_merge(parent::getOptions() , $options);
return $options;
}
}
The new field type displays a drop-down list of messages to choose from. You can see the result of this change in the menu manager section for the helloworld item.
Display the chosen message[edit]
When a menu item of this component is created/updated, Joomla stores the identifier of the message. The HelloWorldModelHelloWorld model has now to compute the message according to this identifier and the data stored in the database.
Modify the site/models/helloworld.php file:
site/models/helloworld.php
<?php
// No direct access to this file
defined('_JEXEC') or die('Restricted access');
// import Joomla modelitem library
jimport('joomla.application.component.modelitem');
/**
* HelloWorld Model
*/
class HelloWorldModelHelloWorld extends JModelItem
{
/**
* @var string msg
*/
protected $msg;
/**
* Get the message
* @return string The message to be displayed to the user
*/
public function getMsg()
{
if (!isset($this->msg))
{
$id = JRequest::getInt('id');
// Get a TableHelloWorld instance
$table = $this->getTable();
// Load the message
$table->load($id);
// Assign the message
$this->msg = $table->greeting;
}
return $this->msg;
}
}
The model now asks the TableHelloWorld to get the message. This table class has to be defined in admin/tables/helloworld.php file
admin/tables/helloworld.php
<?php
// No direct access
defined('_JEXEC') or die('Restricted access');
// import Joomla table library
jimport('joomla.database.table');
/**
* Hello Table class
*/
class HelloWorldTableHelloWorld extends JTable
{
/**
* Constructor
*
* @param object Database connector object
*/
function __construct(&$db)
{
parent::__construct('#__helloworld', 'id', $db);
}
}
You shouldn't see any differences, but if you access the database you should see a table named jos_helloworld with two columns: id and greeting. And two entries: Hello World! and Good bye World
Packaging the component[edit]
Content of your code directory
- helloworld.xml
- site/index.html
- site/helloworld.php
- site/controller.php
- site/views/index.html
- site/views/helloworld/index.html
- site/views/helloworld/view.html.php
- site/views/helloworld/tmpl/index.html
- site/views/helloworld/tmpl/default.xml
- site/views/helloworld/tmpl/default.php
- site/models/index.html
- site/models/helloworld.php
- admin/index.html
- admin/helloworld.php
- admin/sql/index.html
- admin/sql/install.mysql.utf8.sql
- admin/sql/uninstall.mysql.utf8.sql
- admin/models/index.html
- admin/models/fields/index.html
- admin/models/fields/helloworld.php
- admin/tables/index.html
- admin/tables/helloworld.php
Create a compressed file of this directory or directly download the archive and install it using the extension manager of Joomla!1.6. You can add a menu item of this component using the menu manager in the backend.
[edit]
Prev: Adding a variable request in the menu type Next: Basic backend
Contributors[edit]
Italic text