How do i throw a redirect in Laravel Controller if the value doesn't exist in the database?

Question

I have a dropdown category select tag that stores the session and matches the session name to the category slug that stored in the database. Everything works well but if a category name that doesn't exist in the database i get this error Trying to get property 'catslug' of non-object . How do i fix this problem here my code:

 public function catbusiness(Request $request, $slug)
    {
       //this grabs all category in select tag
       $cats =  Category::orderBy('categoryname','ASC')->get();

        //this is the slug for individual category in url
        $catbread = Category::where('catslug', $slug)->first();

        session()->put('categoryname', $catbread->catslug);

        ->with('catbread', $catbread)

    }

view.blade.php

<select name="record" style="margin-top:5%;">
                    @foreach($cats as $categoryselect)
                    <option value="{{ $categoryselect->catslug  }}"
                        @if(session('categoryname') == $categoryselect->catslug)
                            selected="selected"
                        @endif >
                        {{ $categoryselect->categoryname }}
                    </option>
                @endforeach
                </select>

Answer 1

You can check if a category exists by using the exists() method like this:

if(!Category::where('catslug', $slug)->exists()) //Check if the category exists.
{
    return redirect()->route('your_not_found_route'); //Make a redirect
}
$catbread = Category::where('catslug', $slug)->first(); //If category exists fetch its data