Checking for the existence of a child model in volt causes "Call to a member function on a non-object"

Question

Checking for the existence of a child model in volt causes "Call to a member function on a non-object"

blm14 Jan '16

Created Jan '16	Last Reply Jan '16	Replies 1	Views 436	Votes 0

blm14 40.7k

Jan '16

I have two models, PatientList and CodeList. Several fields in PatientList map to CodeList and those fields can sometimes be null. From PatientList initialize():

 public function initialize(){
    parent::initialize();
    $this->hasOne("study_status","dbsr\Models\CodeList","id",array("alias"=>"StudyStatusChild"));
    $this->hasOne("followup_status","dbsr\Models\CodeList","id",array("alias"=>"FollowupStatusChild"));
  }

Then inside the volt I have:

        <td>{% if patient.getStudyStatus() == '' %} &nbsp; {% else %} {{ patient.getStudyStatusChild().getValue('codelist_value')}}{% endif%}</td>
        <td>{% if patient.getFollowupStatus() == ''  %} &nbsp; {% else %}  {{ patient.getFollowupStatusChild().getValue('codelist_value')}} {%endif%}</td>

In cases where getFollowupStatus() or getStudyStatus() are blank, the code inside the {% else %} appears to still be evaluated, and the object is null so it throws an error. How can I display the contents of child records in the case that they are sometimes blank?

alexcore · Answer 1 · 2016-01-15T15:16:42-07:00

It seems that condition in if-statement return non false value but patient model has not child object by this value. May be structural integrity of your table is broken.

blm14 · Answer 2 · 2016-01-19T09:22:40-07:00

That is not the problem. This page contains a Paginator, and there is an area where users can filter which rows are displayed in the results.

$query = Criteria::fromInput($this->di,'dbsr\Models\PatientList',$this->request->get());

I also added a date filter, but it's a range, so I can't just use the same field names, because there is a start and end date. So I did this, after creating the query:

      if($this->request->get("appt_start_date") ){
    $query->andWhere('apt_date >= :appt_start_date:',array('appt_start_date'=>$this->request->get('appt_start_date','string')));
      }

      if($this->request->get("appt_end_date") ){
    $query->andWhere('apt_date <= :appt_end_date:',array('appt_end_date'=>$this->request->get('appt_end_date','string')));
      }

If those lines are not called, the page renders properly, even in cases with rows where the child object is blank. If I try and do a date filter it throws up on the rows with no child object. Why would that matter?

blm14 · Answer 3 · 2016-01-19T09:26:50-07:00

I think it has something to do with hydration mode. When I do addWhere it isn't hydrating the child records in the same way as when I don't

blm14 · Answer 4 · 2016-01-19T09:39:41-07:00

Argh! OK - it was a row that had the foreign key = 0 instead of null. Updating it to null fixed the problem. You were correct!