Do you mean using the admin panel of dashboard framework? Could you please describe more details of your case.

In this case, you need to create a column "Courses" inside Student resource which has the Select2 multiple selection as input. This column is only available in Update and Create screen. In this Select2 input will be provided list of courses inside dataSource(). When the UpdateScreen/CreateScreen of student open, The Select2 will allow you to select one or more courses. When click Save, list of course id will be sent to server in format of array. Admin panel will help to convey those data to methods called updateRecord($conditions, $data) and createRecord($data) depend on screens.

These methods can be overwritten inside Student resource. So what you do inside that updateRecord() and createRecord() is to create/update student, and insert/update the list of course to the StudentCourse (linked table).

Ok, please give me some time, I will write some pseudo code for you.

Hi Eugene, the code will be something like this:

You need first to create a CourseField, a virtual field to mange the list of courses in student table:

<?php

use demo\AdminAutoMaker;
use koolreport\dashboard\Field;

class CourseField extends Field
{
    protected $oriValue = null; // Use this value to avoid multiple query to database
    protected function onCreated()
    {
        $this->valueType("array");
    }

    public function orginalValue()
    {
        if($this->oriValue === null)
        {
            // Make query to database to get list of couses of particular student
            $arrayStudentCourseIds = AdminAutoMaker::table("student_course")
                    ->select("course_id")
                    ->where("student_id",$this->row["student_id"])
                    ->run()
                    ->pluck("course_id");
            //Save to oriValue
            $this->oriValue = $arrayStudentCourseIds;
        }
        return $this->oriValue;
    }

    public function defaultFormatValue($value, $row = null)
    {
        // To show list of student courses in array formats
        return json_encode($value);
    }
}

Now in the Student resource, you do this:

<?php

use koolreport\dashboard\admin\Resource;
use demo\AdminAutoMaker;
use koolreport\dashboard\fields\ID;
use koolreport\dashboard\fields\Text;
use koolreport\dashboard\inputs\Select2;

class Student extends Resource
{
    protected function onCreated()
    {
        $this->manageTable("students")->inSource(AdminAutoMaker::class);
    }

    protected function fields()
    {
        return [
            ID::create("student_id"),
            Text::create("student_name"),
            Text::create("student_email"),
            Text::create("student_phone"),
            Text::create("student_address"),
            CourseField::create("courses")
                ->inputWidget(
                    Select2::create()
                        ->dataSource(function(){
                            return AdminAutoMaker::table("courses")
                                ->select("course_id","course_name");
                        })
                        ->multiple(true)
                        ->value("course_id")
                        ->text("course_name")
                )
                ->showOnAll(false)
                ->showOnCreate(true)
                ->showOnUpdate(true)
        ];
    }

    public function createRecord($data)
    {

        $couses = null;
        if(isset($data["courses"])) {
            $courses = $data["courses"];
            unset($data["courses"]);
        }
        $result = parent::createRecord($data);
        if($result === false) {
            return false;
        }
        //Now we will insert student courses into student_course table
        if(is_array($courses)) {
            foreach($courses as $course_id) {
                AdminAutoMaker::table("student_course")->insert([
                    "student_id"=>$data["student_id"],
                    "course_id"=>$course_id
                ])->run();
            }
        }
        return true;
    }

    public function updateRecord($ids,$data)
    {
        $couses = null;
        if(isset($data["courses"])) {
            $courses = $data["courses"];
            unset($data["courses"]);
        }

        $result = parent::updateRecord($ids,$data);
        if($result === false) {
            return false;
        }

        //Now we delete all records in student_course table
        AdminAutoMaker::table("student_course")
            ->where("student_id",$data["student_id"])
            ->delete()
            ->run();

        //And then insert again
        if(is_array($courses)) {
            foreach($courses as $course_id) {
                AdminAutoMaker::table("student_course")->insert([
                    "student_id"=>$data["student_id"],
                    "course_id"=>$course_id
                ])->run();
            }
        }
        return true;
    }

}

Hope that helps.

Yeah, you are right. Let me a little time consulting with dev.team to find solution.