Doctrine_manual-1-2-en

Chapter 15: Inheritance 238
echo get_class($user); // User
If we do the same thing as above but for the Group record, it will return an instance of
Group.
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15-24
// test.php
// ...
$q = Doctrine_Query::create()
->from('Entity e')
->where('e.id = ?');
$group = $q->fetchOne(array($group->id));
echo get_class($group); // Group
The above is possible because of the type column. Doctrine knows which class each record
was created by, so when data is being hydrated it can be hydrated in to the appropriate
sub-class.
We can also query the individual User or Group models:
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15-25
$q = Doctrine_Query::create()
->select('u.id')
->from('User u');
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15-26
echo $q->getSqlQuery();
The above call to getSql() would output the following SQL query:
SELECT
e.id AS e__id
FROM entity e
WHERE (e.type = '1')
Notice how the type condition was automatically added to the query so that it will only
return records that are of type User.
Conclusion
Now that we've learned about how to take advantage of PHPs inheritance features with our
models we can move on to learning about Doctrine Behaviors (page 239). This is one of the
most sophisticated and useful features in Doctrine for accomplishing complex models with
small and easy to maintain code.
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