Question

DB table:

• Mcourse(Master course )-> contains Course Names
• Lcourse(Linked
  Course- courses belongs to a college) -> contains foreign key
  Mcourse_Id. & college Id.

Nw the problem is

I want to display list of courses available in a college using dropdownlist.

So sql query is:

select Lcourse_Id, Mcourse_Name* from Lcourse inner join Mcourse on Lcourse_Mcourse_Id=Mcourse Id..

*Id & value pair for dropdownlist

I could do this usin createCommand..Its working pretty fine. But i cant do this usin Relations ..Help me.

Answer 1

Let’s imagine for a minute that your Mcourse table is called courses and model for that table is called Courses, your Lcourse table is called courses_colleges and your colleges table is colleges and model for that table is Colleges

Now, You should have Courses model with relations:

public function relations() {
    return array(
        'colleges' => array(self::MANY_MANY, 'Colleges', 'courses_colleges(course_id, college_id)')
    );
}

Your Colleges model should have similar relations:

public function relations() {
    return array(
        'courses' => array(self::MANY_MANY, 'Courses', 'courses_colleges(college_id, course_id)')
    );
}

Now if you want to print out a dropdown with all courses available for a certain college. In your controller action method get the model of that college including its courses:

public function actionShow() {
    $id = 1; // We set just some sample id. You could get it from request ofc.
    $college = Colleges::model()->with('courses')->findByPk($id);
    $this->render('show', array('college'=>$college));
}

Now in your view print out this:

echo CHtml::dropDownList('courses', '', CHtml::listData($college->courses, 'id', 'name'));

Where 'id' and 'name' are columns of your Courses model.

Something like that.