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POOOP approach for wrapping subclasses of database rows
 

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    <p>Let's say I want to store dogs in a database table with each dog having its own subclass in PHP.</p> <p>Basically I want to avoid storing/listing the subclass names in different places in the code. What would be a good OOP approach for that?</p> <pre><code>abstract class Dog { protected $data; public function __construct($data) { $this-&gt;data = $data; } public function name() { return $this-&gt;data["name"]; } abstract public function breed(); } class GermanShepherd extends Dog { public function breed() { return _("German Shepherd"); } } class BullDog extends Dog { public function breed() { return _("Bulldog"); } } </code></pre> <p>Now I have this class that handles groups of objects (i.e. dogs):</p> <pre><code>class Dogs { public static function getDogs() { // ... $ret = array(); while ($row = mysql_fetch_assoc()) { switch ($row["type"]) { // I could do this using a lookup array case "shepherd": $dog = "GermanShepherd"; break; case "bulldog": $dog = "Bulldog"; break; } $ret[] = new $dog($row); } return $ret; } } </code></pre> <p>And I would like to use this class to get the dog types in my view (especially for an <strong>add dog</strong> form), instead of listing the class names:</p> <pre><code>?&gt;&lt;form&gt;&lt;select name="type"&gt;&lt;?php foreach (array("GermanShepherd", "Bulldog") as $dog) { // here I would like to do avoid listing the class names again ?&gt;&lt;option value="&lt;?=$dog ?&gt;"&gt;&lt;?php $d = new $dog; // actually I can't instantiate the class here because I don't have any data at this point echo $d-&gt;name(); ?&gt;&lt;/option&gt;&lt;?php } ?&gt;&lt;/select&gt;&lt;/form&gt;&lt;?php </code></pre> <p>I would like to incorporate this into the <code>Dogs</code> class, something along the lines of this:</p> <pre><code>class Dogs { private static $dogs = array( "shepherd" =&gt; "GermanShepherd", "bulldog" =&gt; "Bulldog", ); public static function getDogs() { // ... $ret = array(); while ($row = mysql_fetch_assoc()) { $dog = self::$dogs[$row["type"]]; $ret[] = new $dog($row); } return $ret; } public static function getDogTypes() { return array_values(self::$dogs); } } ?&gt;&lt;form&gt;&lt;select name="type"&gt;&lt;?php foreach (Dogs::getDogTypes() as $dog) { ?&gt;&lt;option value="&lt;?=$dog ?&gt;"&gt;&lt;?php $d = new $dog; // here I still need to instantiate the class and I don't have any data to provide it with echo $d-&gt;name(); ?&gt;&lt;/option&gt;&lt;?php } ?&gt;&lt;/select&gt;&lt;/form&gt;&lt;?php </code></pre> <p>This would somewhat work so far, but what if I need more class specific information, for example when I have more fields specific to a dog type?</p> <pre><code>foreach (Dogs::getDogTypes() as $dog) { $d = new $dog; // instantiate again? foreach ($d-&gt;formFields() as $f) { // I wouldn't do it like this, just putting this here for demonstrative purposes echo $f; } } </code></pre> <p>I think part of the problem lies in the fact that I need to be able to use my classes with and without database data: Everything seems very reasonable when I have the data from the database table, but I also need the data when I generate the form when creating a new dog.</p> <p>Thanks for your ideas!</p>
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