CRUD operation using node

### CRUD Operations

CRUD (Create, Read, Update, Delete) is an acronym for ways one can operate on stored data. It refers to operations performed in a database.

There is some HTTP method that is used to operate CRUD operation.

POST Method :

The POST method is used to create subordinate or new resources. When creating a new resource, POST to the parent and the service takes care of associating the new resource with the parent, assigning an ID.

For example,

app.post('/products', async (req, res) => {
            const product = req.body;
            console.log(product)
            const result = await productsCollection.insertOne(product);
            res.json(result);
        });

GET Method:

The HTTP GET method is used to read a representation of a resource and returns a representation in XML or JSON and an HTTP response code of 200 (OK).

For example,

  app.get('/products', async (req, res) => {
            const cursor = productsCollection.find({})
            const products = await cursor.toArray();
            res.json(products);
        })

PUT Method:

PUT is used for update capabilities, PUT-ing to a known resource URI with the request body containing the newly-updated representation of the original resource.

For example,

 app.put('/users', async (req, res) => {
            const user = req.body;
            const filter = { email: user.email }
            const options = { upsert: true }
            const updateDoc = { $set: user }
            const result = await usersCollection.updateOne(filter, updateDoc, options)
            res.json(result);
        });

PATCH Method:

PATCH is used to modify capabilities. The PATCH request only needs to contain the changes to the resource, not the complete resource.

For example,

PATCH /user/jthijssen HTTP/1.1
<user>
    <firstname>Joshua</firstname>
</user>

DELETE Method:

DELETE is used to delete a resource identified by a URI.

For example,

 app.delete('/orders/:id', async (req, res) => {
            const id = req.params.id;
            const query = { _id: ObjectId(id) }
            const result = await ordersCollection.deleteOne(query);
            res.json(result);
        })

To operate this operation, you have to must install,

npm i cors

npm i mongodb

npm i express

npm i dotenv

And must update in script object,
like,

  "scripts": {
    "start": "node index.js",
    "start-dev": "nodemon index.js",
    "test": "echo \"Error: no test specified\" && exit 1"
  }