檢查數據庫中是否存在該行

Question

嗨，我要在數據庫中插入一些行，我想檢查該值是否存在，然后不插入，如果不存在，則插入它，這就是我的控制器：

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

use App\Http\Requests;
use App\Http\Controllers\Controller;
use Input;
use Auth;
use App\User;
use App\Product;
use DB;

class listController extends Controller
{
    //
    public function getIndex(Request $request){
        $user_id=Auth::user()->id;
        $list=DB::table('wishlist')
                ->join('products','wishlist.product_id','=','products.id')
                ->join('users','wishlist.user_id','=','users.id')
                ->select('wishlist.id','wishlist.product_id','wishlist.user_id',
                    'products.id as p_id','products.name','products.salary','products.image_name',
                    'users.id as u_id')
                ->where('wishlist.user_id','=',$user_id)
                ->get();

        return view('contents.wishlist')->with('list',$list);
    }
    public function postIndex(Request $request){
        $id=$request->input('id');
        $user_id=Auth::user()->id;
        $product_id =$request['product_id'];


        DB::table('wishlist')->insert(['id'=>$id,'user_id'=>$user_id,'product_id'=>$product_id]);
        return redirect('wishlist');
    }
    public function deleteDeleteProduct(Request $request,$id){
        $pro=$request->get('id');
        DB::table('wishlist')->where('id',$pro)->delete();
        return redirect('wishlist');
    }
}

誰能幫我檢查是否存在？

Answer 1

答案是這樣使用count函數：

public function postIndex(Request $request){

        $id=$request->input('id');
        $user_id=Auth::user()->id;
        $product_id =$request['product_id'];

        $wishlist=DB::table('wishlist')
                    ->where('user_id','=',$user_id)
                    ->where('product_id','=',$product_id)
                    ->count();

        if($wishlist > 0){
            return redirect('wishlist');
        }
        else{
            DB::table('wishlist')
              ->insert(['id'=>$id,'user_id'=>$user_id,'product_id'=>$product_id]);
            return redirect('wishlist');
        }
}

Answer 2

如果您使用的是mysql ，則可以使用INSERT IGNORE和laravel的原始查詢

唯一的條件是您在表的列上定義了UNIQUE索引。

DB::insert(
     'insert ignore into wishlist (id, user_id, product_id) values (?, ?)', 
     [$id, $user_id, $product_id]
);

Answer 3

基本上，您可以從願望清單表中運行查詢以搜索該特定產品。 此后，如果查詢沒有結果，則插入數據。 例如，

$found = DB::table('wishlist')->where('name', $product_name)->first();
if (!$found) {
   //insert to table
}