如果数据库中存在值，则不保存 Laravel

Question

我正在创建一个心愿单，用户可以在其中保存自己的产品并进行保存。我想要的是用户不能多次保存产品。所以，我正在做的是，如果 product_id 存在于数据库中，我不想保存新记录。

这是我的代码，我做错了什么？

public function addWishlist(Wishlist $wishlist) {        
    $wishlist->user_id = request('user_id');
    $wishlist->product_id = request('product_id');

    if(DB::table('wishlists')->where('product_id' !== $wishlist->product_id)) {
        $wishlist->save();
        return redirect()->back();
    }
}

Answer 1

public function addWishlist(Wishlist $wishlist) {   

    if(DB::table('wishlists')->where(['user_id'=>$user_id,'product_id'=>$wishlist->product_id])->exists()){
         // record already exist 
         return redirect()->back();
    }else{
         // record not exist , save the record
         $withlist = new Wishlist();     
         $wishlist->user_id = request('user_id');
         $wishlist->product_id = request('product_id');
         $wishlist->save();
         return redirect()->back();
    }
}

Answer 2

这个呢

public function addWishlist(Wishlist $wishlist) {  
    $userId = request('user_id');
    $productId = request('product_id');

    $found = Wishlist::where('user_id', $userId)->where('product_id', $productId)->count();

    if($found == 0) {
        $wishlist->user_id = $userId;
        $wishlist->product_id = $productId;
        $wishlist->save();
        return redirect()->back();
    }
}

Answer 3

您可以使用 firstOrNew，您需要检查 user_id 和 product_id 组合

    $wishlist::firstOrNew(array('user_id' => request('user_id'),'product_id'=>request('product_id')));
    $wishlist->user_id = request('user_id');
    $wishlist->product_id = request('product_id');
    $wishlist->save();
    return redirect()->back();

Answer 4

你试过 firstOrCreate()

 $user = User::firstOrCreate(['email' => $email])

如果数据库中存在值，则不保存 Laravel

If value exist in database don't save Laravel

php

laravel

laravel-5.5