# Creating Mongoose Model And Making MongoDB Connection For Storing Our Todos

In this section, we will create a Mongoose `model` for our Todo app. If you don't know what is Mongoose, how to create a `schema` and `model` using it, refer to this [tutorial](https://blog.teachmebro.com/building-a-crud-application-using-node-js-and-mongodb-atlas) to know more.

So before connecting with the `MongoDB database` we need to structure how we are going to `model our data` for todo. In our case which fields we will need to store the information about a `todo task`.

Task model
----------

- **taskID** - to uniquely identify the task

- **description** - to store description about a task

- **completed** - this will hold boolean value and it will help us to determine whether the task is completed or uncompleted

These fields are sufficient for a basic `todo app` to store information about a **task**, we can easily perform `CRUD` operation on this model.

So we have **finalized** the fields for our `model`, so now let's move ahead and create our `mongoose schema model`. 

Mongoose Schema Model
---------------------

Mongoose is an `Object Data Modeling` (ODM) library for MongoDB and Node.js. It manages relationships between data, provides schema validation, and is used to translate between objects in code and the representation of those objects in MongoDB.

I know the definition would not have made much sense to you so let me explain it to you in simple words.

Mongodb is `schema less` database so to enforce a `definite schema` on the database mongoose is used, along with the power of noSQL, it has in-built validation, we can define on our schemas.

To learn more about mongoose checkout this tutorial [here](https://blog.teachmebro.com/building-a-crud-application-using-node-js-and-mongodb-atlas).

Creating Todo Model
----------

`Model` is an object representation of data in the database. 

Install following packages:

```
npm install mongoose uniquid
```

We had installed the `mongoose` and `uniquid` packages to generate unique ids for `taskID`.

So, Let's create a file `models/todo.js` with the content:

```
// import mongoose
const mongoose = require("mongoose");

// reference to Schema from mongoose
const Schema = mongoose.Schema;

// creating and defining the schema
const todoSchema = new Schema(
{

  taskID: {

    type: String,

    required: true,

  },

  description: {

    type: String,

    required: true,

  },

  completed: {

    type: Boolean,

    default: false,

  },

},

{

  timestamps: true,

}

);

// use the schema to create a model
var Todos = mongoose.model("Todo", todoSchema);

// export the Todos model to use inside other modules(js files)
module.exports = Todos;
```

So now our `Todo model` is ready we can now move on to make a `database connection` with the `MongoDB` for that we are going to use `MongoDB Atlas`.


## Making Database Connection​​

Now follow the steps in this [blog](https://dev.to/dalalrohit/how-to-connect-to-mongodb-atlas-using-node-js-k9i) and get the `database url` which will look like this:

`mongodb+srv://sample_user:<password>@my-sample-cluster-b3ugy.mongodb.net/<dbname>?retryWrites=true&w=majority`

Now, Add the below line in the `.env` file, complete the `database string` with your `password`and `database name`

```
DATABASE_URL=mongodb+srv://sample_user:<password>@my-sample-cluster-b3ugy.mongodb.net/<dbname>?retryWrites=true&w=majority
```

**Updated .env**

.env

```
PORT=3000

DATABASE_URL=mongodb+srv://sample_user:<password>@my-sample-cluster-b3ugy.mongodb.net/<dbname>?retryWrites=true&w=majority
```

Making Database Connection
--------------------------

Open `app.js` file

Import mongoose

```
const mongoose = require("mongoose");
```

Add this line below where `PORT` is defined:

```
const dbURI = process.env.DATABASE_URL;
```

now create a database connection

```
// making database object 
const connect = mongoose.connect(dbURI, {

  useNewUrlParser: true,

  useUnifiedTopology: true,

});

// connecting with database
connect.then(

  (db) => {

    console.log("Connected Successfully to Mongodb Server");

  },

  (err) => {

    console.log(err);
  }

);

```

Update `app.js`

```
// import express
const express = require("express");

//import mongoose
const mongoose = require("mongoose");

// import dotenv
const dotenv = require("dotenv");

// load environment variable
dotenv.config({ path: ".env" });

// read env variable using process.env.<your_env_variable_name>

const PORT = process.env.PORT;
const dbURI = process.env.DATABASE_URL;

// making connection object

const connect = mongoose.connect(dbURI, {

  useNewUrlParser: true,

  useUnifiedTopology: true,

});

// connecting with database
connect.then(
  (db) => {

    console.log("Connected Successfully to Mongodb Server");

  },

  (err) => {

    console.log(err);

  }

);

// initialize express app
const app = express();

// sending a hello response on visiting http://localhost:3000/
app.get("/", (req, res) => {

  res

    .status(200)

    .json({ message: "Hi I am Server", data: "no data on this endpoint" });

});

// listening for any HTTP requests on PORT 3000
app.listen(PORT, () => {

  console.log(`Server is running at http://localhost:${PORT}`);

});
```

`Restart` your server and you should see the following `output` in your terminal:

**Output:**

```
Server is running at http://localhost:3000

Connected Successfully to Mongodb Server
```

Now we are successfully `connected` with the database and now we can move on to create `routes` and `controllers`.

​