Sequelize中的高效查询

Question

I am implementing a post upvote system that limits by IP. So far, the route for upvoting a single post contains 4 total queries in order to complete these steps:

1. Look for an already existing upvote with same PostId and IP and fail if one exists

-otherwise-

2. Create an upvote
3. Find the post to associate the upvote with and associate them.
4. Lastly re-fetch the post to include the upvote that was just associated.

I feel like the last two steps could be combined, however if I just return the post after associating the upvote to it, it is not included which makes sense because when it was found it had no upvote associated. Here is what I currently have and I feel it's very inefficient for a single upvote.

router.get('/posts/:id/upvote', function(req, res) {
    var id = req.params.id;
    var query_options = {
        where: {
            id: id
        },
        include: common_includes
    };

    // Look for already existing upvote with same PostId and IP.
    Upvote.findOne({ where: { ip: req.ip, PostId: id }}).then(function(upvote) {
        if (upvote !== null) return res.fail('Already upvoted');

        // No upvote exists, create one
        Upvote.create({
            ip: req.ip
        }).then(function(upvote) {
            // Find post to associate upvote with
            Post.findOne({ where: { id: id }}).then(function(post) {
                // Associate upvote to post
                upvote.setPost(post).then(function() {
                    // Query again to get updated post to be returned
                    Post.findOne(query_options).then(function(post) {
                        return res.pass(formatPost(post));
                    }).error(function(err) {
                        console.log(err);
                        return res.fail('Server error');
                    });
                }).error(function(err) {
                    console.log(err);
                    return res.fail('Server error');
                });
            }).error(function(err) {
                console.log(err);
                return res.fail('Server error');
            });
        }).error(function(err) {
            console.log(err);
            return res.fail('Server error');
        });
    });
});

Answer 1

May be helpful http://docs.sequelizejs.com/en/latest/docs/associations/#creating-with-associations .

But IMHO you can combine step 2 and 3 with:

    Upvote.create({
        ip: req.ip,
        PostId: id
    })

and then fetch the new post