DataMapper 1.6.0

[eluser]ntheorist[/eluser]
As for 'has_many' fields, instead of joining one ID and one value column, it uses a subselect to return a count, with the field 'model_count' - (i'm soon implementing a subselect where clause function, so the count field will be based on specified conditions - or even multiple count fields can be used )

Code:

$userclass = new Userclass(); // $has_many = array('user);
$userclass->join_related();
$userclass->get();

// Produces SELECT userclasses.*, (SELECT count(*) FROM `users_userclasses` WHERE `userclass_id` = userclasses.id) AS user_count

foreach($userclass->all as $uc)
{
   echo $uc->name .' has '.$uc->user_count.' Users.';
}

btw, to acommodate being able to sort a query by one of the pseudo-colums 'user_count' or 'userclass_value', i changed the order_by function to

Code:

function order_by($orderby, $direction = '')
{
    // Check if this is a related object
    if ( ! empty($this->related))
    {
        $this->db->order_by($this->table . '.' . $orderby, $direction);
    }
    else if( count($this->has_many) > 0 || count($this->has_one) > 0 )
    {
        $relations = array_merge($this->has_many, $this->has_one);
        
        $model = substr($orderby, 0, (strlen($orderby)-6));
        
        if( ! in_array($model, $relations))
        {
            $this->db->order_by($this->table . '.' . $orderby, $direction);
        }
        else
        {
            $this->db->order_by($orderby, $direction);
        }
    }
    else            
    {
        $this->db->order_by($orderby, $direction);
    }

    // For method chaining
    return $this;
}

which will trigger to order by 'userclass_value' or 'user_count' if 'userclass' and 'user were in fact models in has_one or has_many (conveniently '_value' and '_count' are 6 characters each), otherwise it will assume you are looking for a true column in the parent table and prepend the table name to prevent ambiguity. These are the only two kinds of pseudo columns you can order by so far, but again i'm working to develop this futher and would eventually like to be able to specify an array for display_value

also, you may be wondering how to search the value of a related item:

Code:

function where_related($model, $key, $value = NULL, $type = 'AND ', $escape = TRUE)
{
    $relations = array_merge($this->has_one, $this->has_many);
    
    if(in_array($model, $relations))
    {
        $where_table = $this->{$model}->table;
        
        //$where_value = $key == 'value' ? ( ! empty($this->{$model}->display_value) ? $this->{$model}->display_value : 'id') : 'id';
        
        $this->db->_where($where_table.'.'.$key, $value, $type, $escape);
    }
}

now, i can search through ANY of the userclass tables' columns

Code:

$user = new User();
$user->join_related();
$user->where_related('userclass', 'access >','2');
$user->order_by('userclass_name','asc');
$user->get();

vóila!.. well, it works now for searching thru has_one relations, and i'll be adding the ability to search has_many soon, too. So you could write

Code:

$userclass = new Userclass();
$userclass->join_related();
$userclass->where_count('user >','0');
$userclass->get();

// or even

$userclass->where('name','admin')->where_count('user >','0')->get();

i'm sure i'll be making more modifications on DataMapper to allow for more intricate searches through related items. I was a bit hesitant at first to try subselects, but now it seems its preferable to have one query with a subselect or two, versus up to several hundred separate queries, each of which task the DB and also require loading a new Datamap with its resources, etc..

I think i'm heading into the direction of changing the has_one and has_many arrays and their contents to allow for more dynamic relationship manipulation and explicit configuration, such as changing them to four arrays, each describing the object's relationship to the others:

Code:

$one_one    = array(); // Has and belongs to one object of the specified model
$one_many   = array(); // Belongs to many objects of the specified model
$many_one   = array(); // Many of these belong to one object
$many_many  = array(); // Many of these belong to many other objects

that would prove useful in deletes, updates & saves and such as well, but still have yet to get there.

anyway.. more later. any comments or ideas or criticism is greatly appreciated.

CC