使用Laravel雄辩关系查询有什么优势？

Question

So I'm trying to improve my queries by implementing eloquent relationships. Let's say I have a threads table and each thread have replies

What I need is a JSON object of the information of threads with array of all the replies.

Currently, I can achieve what I want with this.

public function show($threadId){
        $threads = ThreadView::find($threadId);
        $threads->replies = ReplyView::where('threadId', $threadId)->get();
        return response()->json($threads, 200);
    }

With eloquent relationship, I can achieve the same result with something like this.

public function show($threadId) {

    $threads= ThreadView::find($threadId);
    $threads->replies= ThreadView::find($threadId)->Replies;

    return response()->json($threads, 200);
}

Is there an advantage to using relationship? They both look the same to me.

Answer 1

Using Eloquent you can do this even shorter:

public function show($threadId) {
    $threads = ThreadView::with('replies')->find($threadId);
    return response()->json($threads, 200);
}

The with function will eager load relations without you having to write the query.

That is the advantage of Eloquent, it writes the queries for you. No need to create join queries or extra queries for you.

Answer 2

public function show($threadId) {

    $threads= ThreadView::with('replies')->find($threadId);

    return response()->json($threads, 200);
}

The main advantage is that using relationships like this, the first example does 2 selects (it grabs 100% of ThreadView then 100% of ReplyView ), while the second example only does 1 query.

The second advantage is that Eloquent does a Really Good Job at lazy loading compared to others and it is much better to use if you are not an expert in SQL queries.

Ditching Eloquent models and using the DB Builder directly will be approximately 500x faster, and I find the code cleaner. That may be what you're looking for.

But if you use models, use the relationships!