In the following example we make a user management system where
<br /><br />
1. Each user and group are entities
<br /><br />
2. User is an entity of type 0
<br /><br />
3. Group is an entity of type 1
<br /><br />
4. Each entity (user/group) has 0-1 email
<br /><br />
5. Each entity has 0-* phonenumbers
<br /><br />
6. If an entity is saved all its emails and phonenumbers are also saved
<br /><br />
7. If an entity is deleted all its emails and phonenumbers are also deleted
<br /><br />
8. When an entity is created and saved a current timestamp will be assigned to 'created' field
<br /><br />
9. When an entity is updated a current timestamp will be assigned to 'updated' field
<br /><br />
10. Entities will always be fetched in batches

<code type="php">
class Entity extends Doctrine_Record {
    public function setUp() {
        $this->ownsOne("Email","Entity.email_id");
        $this->ownsMany("Phonenumber","Phonenumber.entity_id");
        $this->setAttribute(Doctrine::ATTR_FETCHMODE,Doctrine::FETCH_BATCH);
        $this->setAttribute(Doctrine::ATTR_LISTENER,new EntityListener());
    }
    public function setTableDefinition() {
        $this->hasColumn("name","string",50);
        $this->hasColumn("loginname","string",20);
        $this->hasColumn("password","string",16);
        $this->hasColumn("type","integer",1);
        $this->hasColumn("created","integer",11);
        $this->hasColumn("updated","integer",11);
        $this->hasColumn("email_id","integer");
    }
}
class Group extends Entity {
    public function setUp() {
        parent::setUp();
        $this->hasMany("User","Groupuser.user_id");
        $this->setInheritanceMap(array("type"=>1));
    }
}
class User extends Entity {
    public function setUp() {
        parent::setUp();
        $this->hasMany("Group","Groupuser.group_id");
        $this->setInheritanceMap(array("type"=>0));
    }
}
class Groupuser extends Doctrine_Record { 
    public function setTableDefinition() {
        $this->hasColumn("group_id","integer");
        $this->hasColumn("user_id","integer");
    }
}

class Phonenumber extends Doctrine_Record { 
    public function setTableDefinition() {
        $this->hasColumn("phonenumber","string",20);
        $this->hasColumn("entity_id","integer");
    }
}
class Email extends Doctrine_Record {
    public function setTableDefinition() {
        $this->hasColumn("address","string",150,"email|unique");
    }
}
class EntityListener extends Doctrine_EventListener {
    public function onPreUpdate(Doctrine_Record $record) {
        $record->updated = time();
    }
    public function onPreInsert(Doctrine_Record $record) {
        $record->created  = time();
    }
}

// USER MANAGEMENT SYSTEM IN ACTION:

$manager = Doctrine_Manager::getInstance();

$conn = $manager->openConnection(new PDO("DSN","username","password"));

$user = new User();

$user->name = "Jack Daniels";
$user->Email->address = "jackdaniels@drinkmore.info";
$user->Phonenumber[0]->phonenumber = "123 123";
$user->Phonenumber[1]->phonenumber = "133 133";
$user->save();

$user->Group[0]->name = "beer lovers";
$user->Group[0]->Email->address = "beerlovers@drinkmore.info";
$user->Group[0]->save();

</code>