Question 298974 in PHP Question posted in
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Php – ErrorException Undefined array key in column table of CodeIgniter 4

I am having difficulty getting the blood type description to be displayed in my patients table due to receiving the blood type foreign key in Codeigniter 4.

The error happen in <td><?php echo $p['bt']['description']; ?></td> showing
ErrorException Undefined array key "bt"

  • PacientModel.php
class PacientModel extends Model
{
    ...
    public function bt()
    {
        return $this->belongsTo(BloodTypeModel::class, 'blood_type_id');
    }
}
  • BloodTypeModel.php
class BloodTypeModel extends Model
{
    ...
    public function blood_type()
    {
        return $this->hasMany(PacientModel::class, 'blood_type_id');
    }
}
  • PacientController.php
    public function index()
    {
        $model = new PacientModel();
        $blood_type = new BloodTypeModel();

        $blood_types = $blood_type->findAll();
        $blood_types = array_column($blood_types, null, 'id');

        $pacients = [
            'pacients' => $model->paginate(10),
            'pager' => $model->pager,
            'blood_types' => $blood_types, 
        ];
        return view('pacient/index', $pacients);
    }
  • index.php
  <?php foreach($pacients as $p): ?>
   <tr> 
     <td><?php echo $p['bt']['description']; ?> </td>
   </tr>
  <?php endforeach; ?>
Tags:

2

Answers


  1. 0 
    <?php foreach ($pacients['pacients'] as $p): ?>
<tr>
    <td><?php echo $p->bt->description; ?></td>
</tr>

    Additionally, you might want to eager load the blood type relationship to avoid the N+1 query problem. In your controller, you can modify the query like this

    $pacients = [
    'pacients' => $model->with('bt')->paginate(10),
    'pager' => $model->pager,
];

    This will load the blood type relationship for all the patients in a single query.

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  2. 0

    The issue is CodeIgniter 4 does not support eager loading out of the box, you need to manually join the tables or map the relationships in your controller before passing the data to the view. PacientController.php >>

    public function index()
{
    $model = new PacientModel();
    $pacients = $model->select('pacients.*, blood_types.description as bt_description')
                      ->join('blood_types', 'pacients.blood_type_id = blood_types.id', 'left')
                      ->paginate(10);

    $data = [
        'pacients' => $pacients,
        'pager' => $model->pager
    ];

    return view('pacient/index', $data);
}

    index.php

    <?php foreach($pacients as $p): ?>
<tr> 
  <td><?php echo $p['bt_description']; ?> </td>
</tr>
<?php endforeach; ?>
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