mongoose / MEAN.js - 如果已过滤,model.find()将返回空数组

时间:2014-12-09 17:11:03

标签: javascript node.js mongodb mongoose mean-stack

我是mean.js的新手所以它可能只是错误的语法,但是当我使用带有查询的model.find()时(option.find({poll_id:1})它返回一个空数组。

poll.server.model.js

'use strict';

/**
 * Module dependencies.
 */
var mongoose = require('mongoose'),
    Schema = mongoose.Schema;

/**
 * Poll Schema
 */
var PollSchema = new Schema({
    poll_id: {type:Number},
    user_id: {type:Number},
    poll_question: {type:String},
    poll_language: {type:String},
    poll_description: {type:String},
    poll_description_raw: {type:String},
    poll_weight_additional: {type:Number},
    poll_flag_active:{type:Number,default:1},
    poll_flag_18plus:{type:Number,default:0},
    poll_flag_expire:{type:Number,default:0},
    poll_flag_deleted:{type:Number,default:0},
    poll_flag_moderated:{type:Number,default:0},
    poll_flag_favourised:{type:Number,default:0},
    poll_date_expiration:{type:Date},
    poll_date_inserted:{type:Date,default:Date.now()},
    poll_flag_updated:{type:Date},
    show_thumbs:{type:Number},
    comments:{
        type: Schema.ObjectId,
        ref: 'User'
    }
});

mongoose.model('Poll', PollSchema);

option.server.model.js

'use strict';

/**
 * Module dependencies.
 */
var mongoose = require('mongoose'),
    Schema = mongoose.Schema;

/**
 * Option Schema
 */
var OptionSchema = new Schema({
    option_id:{type:Number},
    poll_id:{type:Number},
    option:{type:Number}
});

mongoose.model('Option', OptionSchema);

polls.server.controller.js

/**
 * Module dependencies.
 */
var mongoose = require('mongoose'),
    errorHandler = require('./errors.server.controller'),
    Poll = mongoose.model('Poll'),
    Option = mongoose.model('Option'),
    _ = require('lodash');

/**
 * List of Polls
 */
exports.list = function(req, res) {
    Poll.find().limit(10).sort('_id')/*.populate('user', 'displayName')*/.exec(function(err, polls) {
        if (err) {

            return res.status(400).send({
                message: errorHandler.getErrorMessage(err)
            });

        } else {
            for (var i=0; i < polls.length; i++) {
                // this works, returns an array with 10 items
                Option.find().exec(function(err,docs){
                    console.log(docs); 
                });
                // this doesnt! although i see in the former array that there are options
                // with the poll_id set to 1.
                Option.find({'poll_id':1}).exec(function(err,docs){
                    console.log(docs); 
                });

            }
            res.json(polls);
        }
    });
};
我在做错了什么?我查了一下,但我没有看到任何帖子提到我的问题。 我尝试使用model.find()。where('poll_id')。equals(1)有和没有引号,但没有。当我运行model.find()它工作,但无论我如何尝试过滤它,它返回一个空数组。感谢adcvance!

1 个答案:

答案 0 :(得分:0)

我知道你是从MySQL导入的,但使用Mongoose存储和搜索你的数据的正确方式将是人口和参考:

var Polls = mongoose.Schema({
  options: [{ type: Schema.Types.ObjectId, ref: 'Options' }]
});

var Options = mongoose.Schema({
  ...
});

Polls
  .find()
  .limit(10)
  .sort('_id')
  .populate('options')
  .exec(function (err, polls) {
    console.log(polls.options); // => [ array of options ]
  });

可在此处找到相关文档http://mongoosejs.com/docs/populate.html

高度建议花一些时间重构您的数据,这样您就可以使用population和refs的许多优点(索引,清理代码等)。不要试图在文档存储上强制使用关系范例。完全撕掉乐队助手或坚持你所得到的知识。

也就是说,你可以用你当前的数据来实现你想要的东西:

// npm install --save async
var async = require('async');

exports.list = function(req, res, next) {

  Poll.find().limit(10).sort('_id').exec(function (err, polls) {

    // In true HTTP parlance, the correct thing to do here would 
    // be to respond with a 500 instead of a 400. The error would
    // be coming from MongoDB, not a poorly formed request by the
    // client. Remember: 40Xs are for client errors and 50Xs are 
    // for server errors. If this is express, you should also look
    // into using a middleware error handler and passing the error 
    // down the line like so:
    if (err) return next(err);

    // Since you used a return statement above, there is no need for 
    // the if/else but this is a matter of style. If it helps with the
    // readability of your code, keep it. I choose to eliminate because
    // async code has enough nesting as it is!

    // https://github.com/caolan/async#maparr-iterator-callback
    async.map(polls, function (poll, callback) {

      // Now look up your option by its poll_id
      Option.find({'poll_id': poll.poll_id}, function (err, options) {
        if (err) return callback(err);
        poll.options = options;
        callback(null, poll);
      });

    }, function (err, data) {

      // Again, this would be a Mongo error, so pass it down the line to
      // handle as a generic 500.
      if (err) return next(err);

      // The data parameter is your newly mapped polls array
      res.json(data);

    });
  });
};    

注意在没有人口和参考的情况下实现了多少样板文件。此外,在封面下,人口只会在数据库中击中两次,而在这里,你要击中它11次。从长远来看,您现在可以更好地更改数据,然后生成关系/文档存储混合体。我见过他们而且他们不漂亮;)