math_cms/app/Models/KnowledgeExplanation.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class KnowledgeExplanation extends Model
{
    protected $table = 'knowledge_explanations';

    protected $fillable = [
        'knowledge_id',
        'teacher_id',
        'student_id',
        'assemble_type',
        'status',
        'kp_codes',
        'case_payload',
        'content_hash',
        'pdf_url',
        'generated_at',
    ];

    protected $casts = [
        'id' => 'integer',
        'teacher_id' => 'string',
        'student_id' => 'string',
        'assemble_type' => 'integer',
        'kp_codes' => 'array',
        'case_payload' => 'array',
        'generated_at' => 'datetime',
    ];
}