node.js - mongoose 在查询 mongolab 数据库时返回空数组/

Question

我是 mongodb 和 mongoose 的新手，我正在尝试按照一本书来学习它。我在 mongolab 上有一个名为“firstdatabase”的现有数据库，其中有一个名为“parking_info”的集合，这是该集合中的一条记录:

{
    "_id": {
        "$oid": "559c152fa439a961c357f931"
    },
    "POST_ID": "354-20160",
    "MS_ID": "-",
    "MS_SPACEID": 0,
    "CAP_COLOR": "Grey",
    "METER_TYPE": "SS",
    "SMART_METE": "Y",
    "ACTIVESENS": "N",
    "JURISDICTI": "SFMTA",
    "ON_OFF_STR": "ON",
    "OSP_ID": 0,
    "STREET_NUM": 2016,
    "STREETNAME": "CHESTNUT ST",
    "STREET_SEG": 3977000,
    "RATEAREA": "Area 5",
    "SFPARKAREA": "Marina",
    "LOCATION": {
        "type": "Point",
        "coordinates": [
            37.8007983983,
            -122.4368696024
        ]
    }
}

我正在尝试使用 mongoose 在 Node.js 应用程序中使用此数据库。这是我的目录结构:

>models
-->parking.js
>views
-->parkings.handlebars
>credentials.ja
>app.js

在 parking.js --> 我正在创建架构。

// mongoose scehma
var mongoose = require('mongoose');
var parkingSchema = mongoose.Schema({
    "POST_ID": String,
    "MS_ID": String,
    "MS_SPACEID": Number,
    "CAP_COLOR": String,
    "METER_TYPE": String,
    "SMART_METE": String,
    "ACTIVESENS": String,
    "JURISDICTI": String,
    "ON_OFF_STR": String,
    "OSP_ID": Number,
    "STREET_NUM": Number,
    "STREETNAME": String,
    "STREET_SEG": Number,
    "RATEAREA": String,
    "SFPARKAREA": String,
    "LOCATION": {
        "type": String,
        "coordinates": [Number]
    }
});

var Parking = mongoose.model('parking_info', parkingSchema);
module.exports = Parking;

在我的 app.js 中我有:

var mongoose = require('mongoose');
var Parking = require('./models/parking');

var opts = {
    server: {
        socketOptions: { keepAlive: 1 }
    }
};
switch(app.get('env')){
    case 'development':
        mongoose.connect(credentials.mongo.development.connectionString, opts);
        console.log('connected..to db');
        break;
    case 'production':
        mongoose.connect(credentials.mongo.production.connectionString, opts);
        break;
    default:
        throw new Error('Unknown execution environment: ' + app.get('env'));
}


app.get("/parkings", function(req, res){
    Parking.find(function(err, parkings){
        if(err){
            console.log('error..');
            return handleError(err);
        }
        else {
            console.log('returning parkings..');
            res.render( "parkings", parkings);
        }

    });

});

我正在尝试显示 parkings.handlebars 中的数据

<h1>Parkings</h1>
{{#each parkings}}
    <div class="parking">
        <h3>{{STREETNAME}}</h3>

    </div>
{{/each}}

但是我的 Parking.find 返回一个空数组，有人可以帮助我理解我哪里出了问题吗？我正在关注 Ethan Brown 所著的《Web Development with Node and Express》一书

Answer 1

解决问题的另一种方法是在模型中显式定义集合名称，即 var Parking = mongoose.model('parking_info', parkingSchema, 'parking_info');。如果未指定集合名称，则使用 Mongoose 约定。

参见:http://mongoosejs.com/docs/api.html#index_Mongoose-model

Parameters:

• name model name
• [schema]
• [collection] name (optional, induced from model name)
• [skipInit] whether to skip initialization (defaults to false)

“当没有传递集合参数时，Mongoose 通过将模型名称传递给 utils.toCollectionName 方法来生成集合名称。此方法使名称复数。如果您不喜欢这种行为，请传递集合名称或设置架构集合名称选项。”