Active Record- How to select a column with relationship? - yii

Question

Projects can have unlimited number of columns (to form a table or something), relationship MANY to MANY. To implement this tbl_project_rel_column is created. It stores project_id, column_id AND pos position of column in Project table.
I am using AC database approach. I have 2 models Project and Column.
Project model's relations method:
public function relations(){
return array(
...
'columns'=>array(self::MANY_MANY,'Column','tbl_project_rel_column('p_id','c_id')
);
}
Now can get all project's columns using something like this:
$model = Project::model()->findbyPk($p_id);
$columns = $model->columns;
But column doesn't store 'pos'(position) value of it's certain project.
How to get 'pos' value of tpl_project_rel_column table of certain project and certain column?

Answer 1

You can use the through feature instead of MANY_MANY. It may also be useful to index the results by the position column. Try something like this:
public function relations()
{
return array(
'projectColumns' => array(self::HAS_MANY, 'ProjectRelColumn', 'p_id', 'index'=>'position'),
'columns' => array(self::HAS_MANY, 'Column', 'c_id', 'through'=>'projectColumns'),
}
Now you can query for projects with columns like this:
$projects = Project::model()->with('columns')->findAll();
foreach($projects as $project) {
// projectColumns are indexed by position. You can sort by this now:
ksort($project->projectColumns)
foreach($project->projectColumns as $pos => $projectColumn)
echo "Pos: $pos Column: {$projectColumn->column->name}";
}