Creating compound attributes in Yii
Let’s say you have a database table called persons with separate attributes (fields) for lastName and firstNames. Elsewhere in your website, you want to refer to the underlying record in this table using the person’s whole name as a single entity (e.g. to provide a link, for example: <a href="http://example.com/index.php?r=Person/view&id=1">Jane Q. Public</a>.
Sometimes, you might be able to refer to the two attributes separately. For example, if you simply wanted to echo the content in a view somewhere you could use code like this:
<?php echo CHtml::encode($data->person->firstNames) . ' ' . CHtml::encode($data->person->lastName); ?>
This is a little inefficient if you are doing it a lot throughout your site, because you need to keep re-entering the same code correctly over and over again (and avoiding this is a main reason for going with an MVC framework like Yii in the first place). But the real trouble comes if you want to use the attributes in a context where the method you are invoking expects a single attribute—as is the case, for example, with the yii linking method CHtml::link.
The way round this is to create a new compound attribute in your model. This means taking the two underlying attributes in your table and combining them into a single attribute already arranged the way you want that you can then invoke in other methods. Or in this case, adding something like this to the Person model:
public function getFirstNamesLastName()
{
return $this->firstNames . ' ' . $this->lastName;
}
Once this function is declared, you can invoke it, in exactly the same way you would have invoked the “original” attributes lastName or [firstNames], using the attribute name FirstNamesLastName: e.g.
<?php
CHtml::link(CHtml::encode($data->person->FirstNamesLastName),
array('person/view', 'id'=>$data->person->person_id)); ?>
(Note: there is a much more efficient way of encoding this last example using the same principle. See this post).
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