Mongoose，使用 find 选择特定字段 [英] Mongoose, Select a specific field with find

问题描述

我试图只选择一个特定的字段

I'm trying to select only a specific field with

exports.someValue = function(req, res, next) {
    //query with mongoose
    var query = dbSchemas.SomeValue.find({}).select('name');

    query.exec(function (err, someValue) {
        if (err) return next(err);
        res.send(someValue);
    });
};

但在我的 json 响应中，我也收到了 _id，我的文档架构只有两个字段，_id 和 name

But in my json response i'm receiving also the _id, my document schema only has two fiels, _id and name

[{"_id":70672,"name":"SOME VALUE 1"},{"_id":71327,"name":"SOME VALUE 2"}]

为什么???

推荐答案

_id 字段始终存在，除非您明确排除它.使用 - 语法这样做:

The _id field is always present unless you explicitly exclude it. Do so using the - syntax:

exports.someValue = function(req, res, next) {
    //query with mongoose
    var query = dbSchemas.SomeValue.find({}).select('name -_id');

    query.exec(function (err, someValue) {
        if (err) return next(err);
        res.send(someValue);
    });
};

或者显式地通过一个对象:

Or explicitly via an object:

exports.someValue = function(req, res, next) {
    //query with mongoose
    var query = dbSchemas.SomeValue.find({}).select({ "name": 1, "_id": 0});

    query.exec(function (err, someValue) {
        if (err) return next(err);
        res.send(someValue);
    });
};

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