app/Models/Grade.php

@@ -31,6 +31,11 @@ class Grade extends Model
         return $this->belongsToMany(Teacher::class);
     }
 
+    public function lessons(): HasMany
+    {
+        return $this->hasMany(Lesson::class);
+    }
+
     public function scopeFilter(Builder $query): void
     {
         $name = request('name');

app/Models/Lesson.php

@@ -4,6 +4,7 @@ namespace App\Models;
 
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Database\Eloquent\Relations\HasMany;
 
 class Lesson extends Model
@@ -20,4 +21,19 @@ class Lesson extends Model
     {
         return $this->hasMany(Score::class);
     }
+
+    public function grades(): BelongsTo
+    {
+        return $this->belongsTo(Grade::class);
+    }
+
+    public function teachers(): BelongsTo
+    {
+        return $this->belongsTo(Teacher::class);
+    }
+
+    public function subjects(): BelongsTo
+    {
+        return $this->belongsTo(Subject::class);
+    }
 }

app/Models/Subject.php

@@ -6,6 +6,7 @@ use Illuminate\Contracts\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsToMany;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\Relations\MorphOne;
 
 class Subject extends Model
@@ -31,6 +32,11 @@ class Subject extends Model
         return $this->belongsToMany(Student::class)->using(Score::class);
     }
 
+    public function lessons(): HasMany
+    {
+        return $this->hasMany(Lesson::class);
+    }
+
     public function scopeFilter(Builder $query): void
     {
         $name = request('name');

app/Models/Teacher.php

@@ -7,6 +7,7 @@ use Illuminate\Database\Eloquent\Casts\Attribute;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsToMany;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\Relations\MorphOne;
 
 class Teacher extends Model
@@ -35,6 +36,11 @@ class Teacher extends Model
         return $this->morphOne(User::class, 'userable');
     }
 
+    public function lessons(): HasMany
+    {
+        return $this->hasMany(Lesson::class);
+    }
+
     public function scopeFilter(Builder $query): void
     {
         $name = request('name');