在我的应用程序中我需要找到类别,然后我想要这个类别的书籍
const CategorySchema = mongoose.Schema({
displayname: String,
category: String
});
module.exports = mongoose.model('Category', CategorySchema);
}
const BookSchema = mongoose.Schema({
name: String,
img: String,
category: {
type: mongoose.Schema.Types.ObjectId,
ref: 'Category'
}
});
module.exports = mongoose.model('Books', BookSchema);
我需要这样的回应
categories = [
{
category: 'News',
books: [{name:'',id''},{}..]
},
{
category: 'Sports',
books: [{name:'',id''},{}..]
}
];
所以我的代码是这样的
Router.get('/categories/', (req, res) => {
Category.find({}, (err, categories) => {
Promise.all(categories.map(category => {
return Book.find({category: category._id}).then( books => {
return {
category: category,
books: books
};
})
})).then( categories => {
res.json(categories);
})
})
});
请问有人知道这个查询是否有更好的解决方案吗? 谢谢大家!
最佳答案
这个怎么样?
Router.get('/categories/', (req, res) => {
Book.find().populate('category').then( books => {
var categories = {}
for(var i = 0; i < books.length; i++){
categories[books[i].category.displayname] = {
category: books[i].category.displayname
books: categories[books[i].category.displayname].books ? categories[books[i].category.displayname].books.push(books[i]) : [books[i]]
};
}
var result = [];
for(var key in categories){
result.push(categories[key])
}
return result;
});
});
它可能更漂亮,但它只向您的数据库发出一个请求,并且应该按照您想要的方式工作
关于javascript - Mongoose Find All 然后在其他模式中为每个查找所有,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/46855711/