Mongo DB Sample Code

This is some sample Mongo DB code in a simple Rest API, which has basic CRUD endpoints to refer to as a guide.

Installation

To run this sample code, install the npm packages & run the server.js file.

npm install

node server

Getting Started With Mongo DB

Model

First define a 'model' of the document you are going to store in the database, in the form of JSON in a JS file (Post.js in our case). This model is the structure of the document to be stored in the database.

const mongoose = require("mongoose");

const PostSchema = mongoose.Schema({
  title: {
    type: String,
    required: true,
  },
  desc: {
    type: String,
    required: true,
  },
  date: {
    type: Date,
    default: Date.now,
  },
});

module.exports = mongoose.model("Posts", PostSchema);

Note that we are using mongoose library to interact with Mongo DB. To import the 'Post' model use the following code.

const Post = require("./models/Post");

Connect to Mongo DB

Next, we'll connect with Mongo DB using the credentials provided when creating a cluster (database).

// Connecting to the database
const connectDB = async () => {
  try {
    await mongoose.connect(process.env.DB_CONN, {
      useNewUrlParser: true,
      useUnifiedTopology: true,
    });
    console.log("MongoDB Connected!");
  } catch (err) {
    console.error(err.message);
    process.exit(1);
  }
};
connectDB();

Performing CRUD Operations

Get all the records

The following function returns all the records in the Posts model

await Post.find();

Get a record by Id

To get a record by Id, just pass the Id in the findById() function.

await Post.findById(req.params.id);

Add a new Post to the database

Add a new Post by passing the data as per the model defined earlier. Note that post.save() function has to be called whenever a new post is to be saved to the database.

const post = new Post({
  title: req.body.title,
  desc: req.body.desc,
});
const savedPost = await post.save();

Update a Post in the database

To update a post, first you need to pass in the Id by which the post is identified and then it is updated by using the $set flag.

await Post.updateOne(
  { _id: req.body.id },
  {
    $set: {
      desc: req.body.desc,
    },
  }
);

Delete a Post from the database

To delete a post, simply pass the Id to the remove() function.

await Post.remove({ _id: req.params.id });