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.

I am thinking of a solution that's possible work for Create New record. You can create an your own action and add to Action Group Box. In action, there is a form in which you can add your own inputs. Let take example for Student resource, you can add inputs for "name", "age" ... and extra multiple select2 box for "courses".

After user click submit form, you can get user's inputs in the handle() method through parameters called $form. You get values from form and insert into database by your own including the update to "student_course" table.

How do you think of this solution.

Eugene, we will think about an automatic update solution for many to many relations in AdminTable so that users won't have to write the update mechanism themselves. We will keep you updated in this topic.

Eugene, I think KoolReport's previous answer could work if we build a "courses" data column for the Student table by using both sql for joining tables and some PHP processes to merge rows of the same student with different courses into one row.

Then you could display the "courses" column, edit it with Select2 and save it into database with custom createRecord and updateRecord methods.

Another solution is to use a separate Resource and AdminTable to manage the StudentsCourses table itself with multiple rows of student id, student name (RelationalLink), course id, course name (RelationalLink).

Another idea: Make a custom form class which can be added into UpdateScreen and CreateScreen. This custom form will be appended to main form, has its own update/create mechanism. Something like this:

class MyCoursesForm extends ExtraForm
{
    protected function form($row)
    {
        $defaultValue = null;
        if(is_array($row)) {
            // If student data is available, get the courses list and put into $defaultValue
            $studentID = $row["student_id"];
        }

        return [
            "Courses"=>Select2::create("courses")
                                    ->defaultValue($defaultValue)
                                    ->dataSource(function(){
                                            return DB::table("courses")->select("id","name");
                                    })
        ];
    }

    protected function handleForm($row)
    {
        $form = $this->getForm();
        $courses = $form->input("courses")->value();
        $studentID = $row["student_id"];
        //Do anything here with db
        
        return true; // Successfully
    }
}

In the Resource we do:

class Student extends Resource
{
    protected function onCreated()
    {
        $this->updateScreen()->extraForm(MyCoursesForm::create());

        $this->createScreen()->extraForm(MyCoursesForm::create());

    }
}

So the Student resource are appeared normal like now. Just that, when update or create, there is extra form appeared together that allow user to input courses.

What i mean is that do you think this idea a good solution? then I we will add this capability.

Awesome, I will tell dev.team to explore this direction.

You can group concat all the courses of each student with this sql query:

SELECT s.studentName, GROUP_CONCAT(c.courseName SEPARATOR ',') as `courses` FROM `students` s join `student_course` sc o on s.studentID = sc.studentID join `courses` c on sc.courseID = c.courseID group by s.studentName;  

Use this courses column for displaying and use custom updateRecord, createRecord when updating it. Let us know if there's any issue with this approach.

This additional column probably needs some small changes in Dashboard's Admin code. Pls send us an email to support@koolreport.com and mention this topic. We will send you an updated version of Dashboard to solve this issue.