This guide explains how to implement CRUD (Create, Read, Update, Delete) operations using Express.js and MongoDB. CRUD is a fundamental concept for interacting with databases and is essential for most web applications.
Prerequisites
- Basic knowledge of JavaScript, Node.js, and Express.js.
- MongoDB installed locally or access to a MongoDB cloud service (e.g., MongoDB Atlas).
npminstalled.
Project Setup
- Initialize a Node.js project:
CODE
mkdir crud-express-mongodb
cd crud-express-mongodb
npm init -y
- Install dependencies:
CODE
npm install express mongoose body-parser cors dotenv
- Create the following folder structure:
CODE
crud-express-mongodb/
|-- models/
|-- routes/
|-- .env
|-- server.js
Step 1: Setup MongoDB Connection
File: .env
CODE
MONGO_URI=mongodb://localhost:27017/crudDB
PORT=5000
File: server.js
CODE
const express = require("express");
const mongoose = require("mongoose");
const bodyParser = require("body-parser");
const cors = require("cors");
require("dotenv").config();
const app = express();
// Middleware
app.use(bodyParser.json());
app.use(cors());
// MongoDB Connection
mongoose
.connect(process.env.MONGO_URI, { useNewUrlParser: true, useUnifiedTopology: true })
.then(() => console.log("MongoDB Connected"))
.catch((err) => console.error("MongoDB connection error:", err));
// Routes
const itemRoutes = require("./routes/itemRoutes");
app.use("/api/items", itemRoutes);
// Start Server
const PORT = process.env.PORT || 5000;
app.listen(PORT, () => console.log(`Server running on port ${PORT}`));
Step 2: Create a MongoDB Schema
File: models/Item.js
CODE
const mongoose = require("mongoose");
const itemSchema = new mongoose.Schema({
name: {
type: String,
required: true,
},
description: {
type: String,
required: true,
},
price: {
type: Number,
required: true,
},
}, { timestamps: true });
module.exports = mongoose.model("Item", itemSchema);
Step 3: Implement CRUD Routes
File: routes/itemRoutes.js
CODE
const express = require("express");
const router = express.Router();
const Item = require("../models/Item");
// Create an item
router.post("/", async (req, res) => {
try {
const newItem = new Item(req.body);
const savedItem = await newItem.save();
res.status(201).json(savedItem);
} catch (err) {
res.status(500).json({ error: err.message });
}
});
// Get all items
router.get("/", async (req, res) => {
try {
const items = await Item.find();
res.status(200).json(items);
} catch (err) {
res.status(500).json({ error: err.message });
}
});
// Get an item by ID
router.get("/:id", async (req, res) => {
try {
const item = await Item.findById(req.params.id);
if (!item) return res.status(404).json({ error: "Item not found" });
res.status(200).json(item);
} catch (err) {
res.status(500).json({ error: err.message });
}
});
// Update an item by ID
router.put("/:id", async (req, res) => {
try {
const updatedItem = await Item.findByIdAndUpdate(req.params.id, req.body, { new: true });
if (!updatedItem) return res.status(404).json({ error: "Item not found" });
res.status(200).json(updatedItem);
} catch (err) {
res.status(500).json({ error: err.message });
}
});
// Delete an item by ID
router.delete("/:id", async (req, res) => {
try {
const deletedItem = await Item.findByIdAndDelete(req.params.id);
if (!deletedItem) return res.status(404).json({ error: "Item not found" });
res.status(200).json({ message: "Item deleted" });
} catch (err) {
res.status(500).json({ error: err.message });
}
});
module.exports = router;
Step 4: Testing the API
Use tools like Postman or cURL to test the following endpoints:
Create an item:
CODE
POST /api/items
Content-Type: application/json
{
"name": "Laptop",
"description": "A powerful laptop",
"price": 1200
}
Get all items:
CODE
GET /api/items
Get an item by ID:
CODE
GET /api/items/:id
Update an item:
CODE
PUT /api/items/:id
Content-Type: application/json
{
"name": "Gaming Laptop",
"description": "A high-end gaming laptop",
"price": 1500
}
Delete an item:
CODE
DELETE /api/items/:id
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