如何使用nodejs在mongodb中的两个不同集合中搜索值

Question

router.post('/api/getproductsbycategory', function(req, res){
var category = req.body.category
Category.getCategoryId(category, function(err, categoryId){
    if(err){
        throw err;
    }
    if(categoryId.length){
        Product.getProductByCid(categoryId[0]._id, function(err, product){
            if(err){
                throw err;
            }
            res.json(product)
        })
    }
})

});

router.post('/api/getproductprice', function(req, res){
var product = req.body.id
Productprice.getProductprice(product, function(err, productprice){
    if(err){
        throw err;
    }
    res.json(productprice)
})

})

I have some products in one collection and the price is in other collection.when I had inserted product unique id with price but when I call more than one product with their price with forEach loop.At that time the value of the product and price goes different many times.I think this is synchronisation problem.what should I for this??

Answer 1

You can do everything in one query, if you already have the category the query on Category model is not needed:

Product
.aggregate([
        $match: {
            category_id: YOUR_CATEGORY_ID
        },
        $lookup: {
            from: "Productprice",
            localField: "category_id", //category_id field inside Product model
            foreignField: "category_id", //category_id field inside Price model
            as: "price"
        },
    ])