PHP How to save an object in a relation?

Data Service
1

Hi

I am cracking my head and studying the examples and forums but just couldn’t get the following to work.
I have 2 tables (main and sub). Main has one-to-many relationship to Sub. So, Main can have many Sub.
I want to create a new Sub and add it to Main. Just couldn’t do it.

Here are my codes:

class Job_group_main {
  
    private $job_description;
    private $subgroup;
    private $objectId;
   
    public function getDescription() {
        return $this->job_description;
    }
  
    public function setDescription( $job_description ) {
        $this->job_description = $job_description;
    }
    
    public function getobjectId() {
        return $this->objectId;
    }
  
    public function setobjectId( $objectId ) {
        $this->objectId = $objectId;
    }
    
  
    public function getSubgroup() {
        return $this->subgroup;
    }
  
    public function setSubgroup( $subgroup ) {
        $this->subgroup = $subgroup;
    }
    
}

class Job_group_sub {
  
    private $job_description;
    private $jobdescriptions;
    private $objectId;
    private $ownerId;
   
    public function getDescription() {
        return $this->job_description;
    }
  
    public function setDescription( $job_description ) {
        $this->job_description = $job_description;
    }
    
    public function getObjectId() {
        return $this->objectId;
    }
  
    public function setObjectId( $ownerId ) {
        $this->ownerId = $ownerId;
    }
    
    public function getOwnerId() {
        return $this->ownerId;
    }
  
    public function setOwnerId( $objectId ) {
        $this->objectId = $objectId;
    }
    
  /*
    public function getSubgroup() {
        return $this->subgroup;
    }
  
    public function setSubgroup( $subgroup ) {
        $this->subgroup = $subgroup;
    }
    */
}
class Job_group_sub {
  
    private $job_description;
    private $jobdescriptions;
    private $objectId;
   
    public function getDescription() {
        return $this->job_description;
    }
  
    public function setDescription( $job_description ) {
        $this->job_description = $job_description;
    }
    
    public function getObjectId() {
        return $this->objectId;
    }
  
    public function setObjectId( $ownerId ) {
        $this->ownerId = $ownerId;
    }
}
$jsc = new Job_group_sub();
$jsc->setDescription( "ABC" );
$jmc = Backendless::$Persistence->of( 'Job_group_main')->findById( $jmc_objectId,2 );

$subgroups = $jmc->getSubgroup();
$subgroups[] = $jsc;
$jmc->setContacts($subgroups); 
$saved_jmc = Backendless::$Persistence->of("Job_group_main")->save( $jmc );

HELP!!

2

What does the implementation of:

$jmc->setContacts

look like?

3

It is a typo
Should be $jmc->setSubgroup

4

Can you please verify that $jmc object contains the proper $subgroup right before the save() call?