Node.JS，Express&MongoDB ::多个集合 [英] Node.JS, Express & MongoDB :: Multiple Collections

问题描述

我正在使用Node.JS，Express，MongoDB和EJS.我有一个问题，关于一个数据库下的多个MongoDB集合，并要求它们在前端使用.我有3个收藏夹，经过大量研究后仍未找到如何正确调用多个收藏夹的方法.

I'm using Node.JS, Express, MongoDB and EJS. I have a question regarding multiple MongoDB collections under one database, and calling them to use on the front-end. I have 3 collections, and after much research haven't found how to call more than one collection without errors.

我知道将所有内容存储在一个集合中并不是什么问题，但是我觉得最好的方法是将它们按类别分开.这是我的数据库/收集呼叫:

I understand that it wouldn't be a problem to store everything under one collection, but I feel like the best approach would be to separate them out by category. Here's my db/collection call:

app.use(express.bodyParser());
var MongoClient = require('mongodb').MongoClient;

app.get('/', function(req, res){
  MongoClient.connect("mongodb://localhost:27017/michael", function(err, db) {
    if(!err) {
      console.log("We are connected");
    }
    db.collection("portfolio", function(err, collection) {
      collection.find().sort({order_num: 1}).toArray(function(err, result) {
        var portfolio = [];
        if (err) {
          throw err;
        } else {
          for (i=0; i<result.length; i++) {
            portfolio[i] = result[i];
          }
          res.render('index.html', {portfolio: portfolio});
        }
      });
    });
  });
});

我如何才能多次调用其他收藏集，例如关于"收藏集等?我尝试添加另一个...

How could I make multiple calls to additional collections, such as an "about" collection, etc? I tried adding another...

db.collection("about", function(err, collection) {

...在...内...

...within...

MongoClient.connect("mongodb://localhost:27017/michael", function(err, db) {

...但是在终端控制台日志中却给我错误.

...but it gives me errors in the Terminal console log.

谢谢.

这就是我想要做的，这给我一个错误:

Here's what I'm trying to do, which gives me an error:

app.get('/', function(req, res){
  MongoClient.connect("mongodb://localhost:27017/michael", function(err, db) {
    if(!err) {
      console.log("We are connected");
    }
    db.collection("portfolio", function(err, collection) {
      collection.find().sort({order_num: 1}).toArray(function(err, result) {
        var portfolio = [];
        if (err) {
          throw err;
        } else {
          for (i=0; i<result.length; i++) {
            portfolio[i] = result[i];
          }
          res.render('index.html', {portfolio: portfolio});
        }
      });
    });
     // Here's the additional collection call:
     db.collection("about", function(err, collection) {
      collection.find().sort({order_num: 1}).toArray(function(err, result) {
        var about = [];
        if (err) {
          throw err;
        } else {
          for (i=0; i<result.length; i++) {
            about[i] = result[i];
          }
          res.render('index.html', {about: about});
        }
      });
    });
  });
});

这是控制台中的错误:

ReferenceError: /Volumes/Files/WebDev/RHC/michael/michael/views/index.html:62
60|               <div class="row-fluid">
61|                 <ul id="work" class="thumbnails">
>> 62|                     <% for(i=0; i<portfolio.length; i++) { %>
63|                         <% if (portfolio[i].proj_type == "work") { %>
64|                             <% var newLine = ""; %>
65|                             <% var fancyBox = ""; %>

portfolio is not defined

因此，在MongoDB中，数据库下有两个集合，称为"michael"，我试图在一个MongoClient.connect()下调用这两个集合.然后，我将结果通过两个数组(通过EJS)发送到前端:组合"和关于".看来，当我这样做时，它将使投资组合"变得不确定.希望有道理.

So I have two collections in MongoDB under the db called "michael", and I'm trying to call both of them under one MongoClient.connect(). I'm then sending the results to the front-end (via EJS) in two arrays: "portfolio" and "about". It seems that when I do this, it renders "portfolio" undefined. Hope that makes sense.

推荐答案

好吧，使用aesede的解决方案以及我自己的修补方法，我得到了它来渲染两个集合.它可能需要一些技巧，但这是我得到的:

Ok, using aesede's solution plus my own tinkering, I got it to render two collections. It could probably use some finessing but here's what I got:

// GLOBAL ARRAYS FOR STORING COLLECTION DATA
var collectionOne = [];
var collectionTwo = [];
app.get('/', function(req, res){
  MongoClient.connect("mongodb://localhost:27017/michael", function(err, db) {
    if(!err) {
      console.log("We are connected");
    }
    db.collection("collectionOne", function(err, collection) {
      collection.find().sort({order_num: 1}).toArray(function(err, result) {
        if (err) {
          throw err;
        } else {
          for (i=0; i<result.length; i++) {
            collectionOne[i] = result[i];
          }
        }
      });
      db.collection("collectionTwo", function(err, collection) {
        collection.find().sort({order_num: 1}).toArray(function(err, result) {
          if (err) {
            throw err;
          } else {
            for (i=0; i<result.length; i++) {
              collectionTwo[i] = result[i];
            }
          }
        });
      });
      // Thank you aesede!
      res.render('index.html', {
        collectionOne: collectionOne,
        collectionTwo: collectionTwo
      });
    });
  });
});

我发现的唯一错误是，当Node重新启动并在浏览器中单击刷新"时，我没有看到HTML呈现的任何内容.但是，随后进行的任何刷新都会始终显示内容.

The only bug, per se, that I found, was that when Node restarted and I hit "refresh" in the browser, I didn't see any content being rendered in the HTML. However, any subsequent refresh showed the content consistently.

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