php - 如果最后一个 id 被删除，则获取下一个 id

Question

我有 bill 和 Product_bill 表。

我需要在product_bill表中使用bill_id，并且我应该首先创建帐单，所以我做了这个

public function store(Request $request)
{

    if( Bill::first() == null )
    {
        $bill_id = 1;
    }
    else {

        $bill_id = Bill::orderBy('id','desc')->first()->id +1 ;
    }
    // dd($bill_id);
    $brand_id = auth('brand')->id();
    $bill = new Bill();
    $bill->brand_id = $brand_id;
    $bill->date = Carbon::today();

    $data = $request->all();
    $products = [];
    $total = 0;
    for($i = 0 ; $i<count($data['id']) ; $i++)
    {   
        $prod = new ProductsBill();
        $prod->product_id = $data['id'][$i] ;
        $prod->quantity = $data['quantity'][$i];
        $prod->bill_id = $bill_id;
        $products[] = $prod->attributesToArray();
        $price = Product::find($prod->product_id)->price;
        $total += $price * $prod->quantity;
    }
    $bill->total = $total;
    $bill->save();
    ProductsBill::insert($products);

    return redirect()->back();

}

当我删除任何账单时，product_bill 表中的新 bill_id 会获取最后一个账单的下一个数字，我需要知道接下来将创建 id谢谢。

Answer 1

如果您对 $bill 变量使用 save() 函数，您将通过访问 $bill->id 获取 id。如果您想确保交易完成，您可以使用DB transactions .

use DB;

class ... {

   ...

    public function store(Request $request)
    {
        $brand_id = auth('brand')->id();
        $bill = new Bill();
        $bill->brand_id = $brand_id;
        $bill->date = Carbon::today();

        DB::beginTransaction();

        try{
            $bill->save();

            $data = $request->all();
            $products = [];
            $total = 0;
            for($i = 0 ; $i<count($data['id']) ; $i++)
            {   
                $prod = new ProductsBill();
                $prod->product_id = $data['id'][$i] ;
                $prod->quantity = $data['quantity'][$i];
                $prod->bill_id = $bill->id;
                $products[] = $prod->attributesToArray();
                $price = Product::find($prod->product_id)->price;
                $total += $price * $prod->quantity;
            }
            $bill->total = $total;
            $bill->save();
            ProductsBill::insert($products);

            DB::commit();

            return redirect()->back();

        } catch(\Illuminate\Database\QueryException $ex){ 
            DB::rollBack();
            // Exception redirect here

        }
    }

    ...

}