I am unable to save or update the data from my frontend, I’m getting this error. I Have a category table, an item table, and a category item (pivot) table.

The following is my Item Controller File Code:

<?php

namespace AppHttpControllers;

use AppModelsItem;
use IlluminateHttpRequest;

class ItemController extends Controller
{
    public function index()
    {
        return Item::all();
    }

    public function show($item)
    {
        return Item::findOrFail($item);
    }

    public function store(Request $request)
    {
        $validatedData = $request->validate([
            'name' => 'required|string|max:255',
            'description' => 'required|string',
            'price' => 'required|numeric|min:0',
            'ingredients' => 'required|string',
            'photo' => 'nullable|string|max:255',
            'category_id' => 'nullable|integer|exists:categories,id',
        ]);

        // Remove the 'category_id' from the validated data
        $categoryId = $validatedData['category_id'] ?? null;
        unset($validatedData['category_id']);

        // Create the item
        $item = Item::create($validatedData);

        // Sync categories if category_id is provided
        if ($categoryId) {
            $item->categories()->sync([$categoryId]);
        }

        return $item;
    }

    public function update(Request $request, $item)
    {
        $validatedData = $request->validate([
            'name' => 'sometimes|required|string|max:255',
            'description' => 'sometimes|required|string',
            'price' => 'sometimes|required|numeric|min:0',
            'ingredients' => 'sometimes|required|string',
            'photo' => 'nullable|string|max:255',
            'category_id' => 'nullable|integer|exists:categories,id',
        ]);

        $item = Item::findOrFail($item);
        $item->update($validatedData);
        
        return $item;
    }
    

    public function destroy($item)
    {
        $item = Item::findOrFail($item);
        $item->delete();
        
        return $item;
    }
}

The following is my Item Resource File Code:

<?php

namespace AppFilamentResources;

use AppFilamentResourcesItemResourcePages;
use AppModelsCategory;
use AppModelsItem;
use FilamentForms;
use FilamentFormsForm;
use FilamentFormsComponentsFileUpload;
use FilamentFormsComponentsTextInput;
use FilamentFormsComponentsTextArea;
use FilamentFormsComponentsSelect;
use FilamentResourcesResource;
use FilamentTables;
use FilamentTablesColumns;
use FilamentTablesColumnsTextColumn;
use FilamentTablesColumnsImageColumn;
use FilamentTablesTable;

class ItemResource extends Resource
{
    protected static ?string $model = Item::class;

    protected static ?string $navigationIcon = 'heroicon-o-squares-2x2';

    public static function form(Form $form): Form
    {
        $categories = Category::with('children')->get();

        // Define a recursive function to format categories and subcategories
        $formatCategories = function ($categories) use (&$formatCategories) {
            $options = [];

            foreach ($categories as $category) {
                $options[$category->id] = $category->name;
                if ($category->children->isNotEmpty()) {
                    $options += $formatCategories($category->children);
                }
            }

            return $options;
        };

        // Format categories and subcategories for select options
        $categoryOptions = $formatCategories($categories);

        return $form
            ->schema([
                TextInput::make('name')->required(),
                FileUpload::make('photo'),
                TextInput::make('price')->required(),
                TextArea::make('description'),
                TextInput::make('ingredients'),
                // Add a drop-down menu for all categories and subcategories
                Select::make('category_id')
                    ->label('Category')
                    ->multiple()
                    ->options($categoryOptions)
                    ->placeholder('Select categories'),
            ]);
    }

    public static function table(Table $table): Table
    {
        return $table
            ->columns([
                TextColumn::make('name'),
                TextColumn::make('description'),
                TextColumn::make('price'),
                ImageColumn::make('photo'),
            ])
            ->filters([
                //
            ])
            ->actions([
                TablesActionsEditAction::make(),
            ])
            ->bulkActions([
                TablesActionsBulkActionGroup::make([
                    TablesActionsDeleteBulkAction::make(),
                ]),
            ]);
    }

    public static function getRelations(): array
    {
        return [
            //
        ];
    }

    public static function getPages(): array
    {
        return [
            'index' => PagesListItems::route('/'),
            'create' => PagesCreateItem::route('/create'),
            'edit' => PagesEditItem::route('/{record}/edit'),
        ];
    }
}

This is what I tried….

When I press save the following happens….