模型关系设置

app/Models/CategoryModal.php

@@ -3,6 +3,7 @@
 namespace App\Models;
 
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 
 /**
  * 分类表
@@ -13,4 +14,13 @@ class CategoryModal extends Model
     protected $table = 'categories';
 
     protected $guarded  = [];
+
+    /**
+     * 项目
+     * @return HasMany
+     */
+    public function projects(): HasMany
+    {
+        return $this->hasMany(ProjectModal::class, 'category_id', 'id');
+    }
 }