使用 mongoose 在 Mongo DB 中搜索和过滤数据

Question

 var questionSchema = new Schema({ category: { name: { type: String, lowercase: true, required: [true, 'Category is a required field'] }, question:[ { q: { type: String, lowercase: true }, options: { option1:{ type: String, lowercase: true }, option2:{ type: String, lowercase: true ] }, option3:{ type: String, lowercase: true }, option4:{ type: String, lowercase: true }, }, ans: { type: String, lowercase: true }, level:{ type: String, lowercase: true } } ] }, }, { strict: true, runSettersOnQuery: true, timestamps: { createdAt: 'created', updatedAt: 'updated' } });

This is my question schema. I am trying to get all the questions of a particular category. Till now I have tried this ---

 function (req,res,next) { console.log(req.params.qcategory); Question.find({ category:{ name: req.params.qcategory, } },'', function (err,data) { if (err) { err.status = 406; return next(err); } console.log(data); return res.status(201).json({ message: ' success.',data:data }) }) };

In req.params.qcategory it contains the name of the category like 'programming' for instance. But it returned me an empty array. **PS. There are questions of programming category in my DB. Then What am i doing wrong ???

Also is there a way to first check what category a question is and then add to the question array inside that particular category. I don't want to add questions with categories again and again instead i want to check if that category already exists in the database and push the question inside the array of that question category. For instance if a question is of 'programming' category and in the database there is already a question which is of again a 'programming' category then push the question inside the array of programming category.

If my questions are not clear then please comment I will respond quickly.

Answer 1

Try this, Not tested

function (req,res,next) {
console.log(req.params.qcategory);
Question.find({
    "category.name": req.params.qcategory,}
 , function (err,data) {
    if (err) {
        err.status = 406;
        return next(err);
    }
    console.log(data);
    return res.status(201).json({
        message: ' success.',data:data
    })
})
};

Replace the {category:{name:req.params.qcategory}} with {"category.name":req.params.qcategory} .

read more on mongodb's Query Embedded Documents https://docs.mongodb.com/.../method/db.collection.find/

Answer 2

Try this.

function (req,res,next) {
    console.log(req.params.qcategory);
    const name = req.params.qcategory;
    Question.find({name})
        .then((data)=>return res.status(201).json({message:"success",data:data})
        .catch(err=> {
            res.status(406)
            return next(err);
        })
};