35 |
36 |
Models
37 |
38 |
What are models?
39 |
40 |
41 | Whenever data needs to be retrieved, manipulated or deleted this should always be done by a model. A Model is a representation of some kind of
42 | data and has the methods to change them. For example: you never put SQL queries in a Controller, those are put in the Model and the Controller will
43 | call upon the Model to execute the queries. This way if your database changes you won't need to change all your Controllers but just the Model that acts upon it.
44 |
45 |
46 |
How are Models used?
47 |
48 |
49 | In Fuel a Model is essentially just a Class like any other. They do nothing more than a library, but the Model_ prefix
50 | helps to differentiate it from other classes. To do something useful with a Model you will need to use other classes.
51 |
52 |
53 |
Creating a model
54 |
55 |
56 | namespace Model;
57 |
58 | class Welcome extends \Model {
59 |
60 | public static function get_results()
61 | {
62 | // Database interactions
63 | }
64 |
65 | }
66 |
67 |
Remember to prefix a backslash to classes you're using from global, outside the namespace
68 | you're in. If you don't understand why, read up on namespaces on
69 | PHP.net.
70 |
71 |
Accessing a model
72 |
73 |
PHP has the use keyword for importing classes into the current namespace, this allows
74 | you to shorten the Model's classname from Model\Welcome to just Welcome
75 | within the file of a specific class:
76 |
77 |
78 | use \Model\Welcome;
79 |
80 | class Controller_Welcome extends Controller
81 | {
82 | public function action_index()
83 | {
84 | $results = Welcome::get_results();
85 | }
86 | }
87 |
88 |
89 |
90 |
Writing your own models
91 |
92 |
While models can be used with any type of data storage we'll focus here on usage with SQL because that's the
93 | most common usage. Almost always your models will have at least all CRUD
94 | methods: create, read, update, delete (or variations on those). In Fuel your models don't need to extend
95 | anything by default, though you can of course create your own base model or use Fuel's
96 | Orm package.
97 |
98 |
Writing SQL Queries
99 |
100 |
You can use the DB class to build queries with native SQL like so:
101 |
102 |
DB::query('SELECT * FROM users WHERE id = 5');
103 |
104 |
Using the Query Builder
105 |
106 |
When it comes to escaping data, working with data in arrays or making an application portable over multiple database engines, you might find native
107 | SQL to be rather cumbersome. Using the Query Builder methods in the DB Class you can abstract writing native SQL:
108 |
109 |
110 |
DB::select('title','content')->from('articles')->execute()->get('title');
111 |
112 |
See more about native SQL queries and using the Query Builder in the DB class documentation.
113 |
114 |
Using Model_Crud to create models
115 |
116 |
One possible way of creating models is by using Model_Crud, which adds a commonly used functionality to your models for interacting with a database table. There's an example of its usage below.
117 |
118 |
// find all articles
119 | $entry = Model_Article::find_all();
120 |
121 | // find all articles from category 1 order descending by date
122 | $entry = Model_Article::find(array(
123 | 'where' => array('category_id', 1),
124 | 'order_by' => array('date' => 'desc')
125 | ));
126 |
127 |
Using the Orm to create models
128 |
129 |
For models with more functionality, like support for relations, you can use the Orm Package, which adds a lot of functionality out-of-the-box to your models. There's an example of its usage below.
130 |
131 |
// find all articles
132 | $entry = Model_Article::find('all');
133 |
134 | // find all articles from category 1 order descending by date
135 | $entry = Model_Article::find('all', array(
136 | 'where' => array('category_id', 1),
137 | 'order_by' => array('date', 'desc')
138 | ));
139 |
140 |
Model_Crud and the ORM package use similar syntax, which makes it simple to migrate once you require more functionality than Model_Crud can provide.
141 |
142 |
24 | Documentation
25 | 
