NW5 Manchester - Mohammed Alhallaq SQL WEEK 03

2-api/.gitignore

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+node_modules/

2-api/dbConnection.js

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+const { Pool } = require("pg");
+
+const pool = new Pool({
+ user: "postgres",
+ password: "cyf",
+ host: "localhost",
+ port: 5432,
+ database: "cyf_ecommerce",
+});
+
+module.exports = pool;

2-api/package.json

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+{
+ "name": "cyf-ecommerce-api",
+ "version": "1.0.0",
+ "main": "server.js",
+ "author": "Mohammed",
+ "license": "MIT",
+ "dependencies": {
+ "express": "^4.18.2",
+ "pg": "^8.9.0"
+ },
+ "devDependencies": {
+ "nodemon": "^2.0.20"
+ },
+ "scripts": {
+ "start": "nodemon server.js"
+ }
+}

2-api/server.js

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+const express = require("express");
+const pool = require("./dbConnection");
+
+const app = express();
+
+app.use(express.json());
+
+// Get All customers End Point
+app.get("/customers", async (req, res) => {
+ try {
+ const result = await pool.query("SELECT * FROM customers");
+ res.json(result.rows);
+ } catch (err) {
+ console.error(err);
+ res.status(500).json({ error: "Internal Server Error" });
+ }
+});
+
+// Get customer by ID API end point
+
+app.get("/customers/:customerId", async (req, res) => {
+ try {
+ const { customerId } = req.params;
+ const query = "SELECT * FROM customers WHERE id = $1";
+ const result = await pool.query(query, [customerId]);
+ if (result.rowCount === 0) {
+ res
+ .status(404)
+ .json({ error: `No customer with ID ${customerId} found` });
+ } else {
+ res.json(result.rows[0]);
+ }
+ } catch (error) {
+ console.error(error);
+ res.status(500).json({ error: "Something went wrong!" });
+ }
+});
+
+//Get All Products or a specific product name End Point
+
+app.get("/products", async (req, res) => {
+ try {
+ const { name } = req.query;
+ let query = `
+ SELECT products.product_name, product_availability.unit_price, suppliers.supplier_name
+ FROM products
+ JOIN product_availability ON products.id = product_availability.prod_id
+ JOIN suppliers ON suppliers.id = product_availability.supp_id
+ WHERE ($1::text IS NULL OR products.product_name ILIKE $1)
+ `;
+ const values = [name ? `%${name}%` : null];
+ const result = await pool.query(query, values);
+ res.json(result.rows);
+ } catch (error) {
+ console.error(error);
+ res.status(500).json({ error: "Something went wrong!" });
+ }
+});
+
+// POST customer API End point
+app.post("/customers", async (req, res) => {
+ try {
+ const { name, address, city, country } = req.body;
+ const query = `
+ INSERT INTO customers (name, address, city, country)
+ VALUES ($1, $2, $3, $4)
+ RETURNING *
+ `;
+ const result = await pool.query(query, [name, address, city, country]);
+ res.status(201).json(result.rows[0]);
+ } catch (error) {
+ console.error(error);
+ res.status(500).json({ error: "Something went wrong!" });
+ }
+});
+
+// POST product API End point
+app.post("/products", async (req, res) => {
+ try {
+ const { product_name } = req.body;
+ const query = `
+ INSERT INTO products (product_name)
+ VALUES ($1)
+ RETURNING *
+ `;
+ const result = await pool.query(query, [product_name]);
+ res.status(201).json(result.rows[0]);
+ } catch (error) {
+ console.error(error);
+ res.status(500).json({ error: "Something went wrong!" });
+ }
+});
+
+//POST Customer order End point
+
+app.post("/customers/:customerId/orders", async (req, res) => {
+ const customerId = req.params.customerId;
+ const { order_date, order_reference } = req.body;
+
+ try {
+ // Check if customer exists
+ const customer = await pool.query("SELECT * FROM customers WHERE id = $1", [
+ customerId,
+ ]);
+ if (customer.rows.length === 0) {
+ return res.status(404).json({ error: "Customer not found." });
+ }
+
+ // Insert new order
+ const query = `
+ INSERT INTO orders (order_date, order_reference, customer_id)
+ VALUES ($1, $2, $3)
+ RETURNING *
+ `;
+ const result = await pool.query(query, [
+ order_date,
+ order_reference,
+ customerId,
+ ]);
+ res.status(201).json(result.rows[0]);
+ } catch (error) {
+ console.error(error);
+ res.status(500).json({ error: "Something went wrong!" });
+ }
+});
+
+// PUT API end point to update Customer Details
+
+app.put("/customers/:customerId", async (req, res) => {
+ const customerId = req.params.customerId;
+ const { name, address, city, country } = req.body;
+
+ try {
+ // Check if customer exists
+ const customer = await pool.query("SELECT * FROM customers WHERE id = $1", [
+ customerId,
+ ]);
+ if (customer.rows.length === 0) {
+ return res.status(404).json({ error: "Customer not found." });
+ }
+
+ // Update customer
+ const query = `
+ UPDATE customers
+ SET name = $1, address = $2, city = $3, country = $4
+ WHERE id = $5
+ RETURNING *
+ `;
+ const result = await pool.query(query, [
+ name,
+ address,
+ city,
+ country,
+ customerId,
+ ]);
+ res.json(result.rows[0]);
+ } catch (error) {
+ console.error(error);
+ res.status(500).json({ error: "Something went wrong!" });
+ }
+});
+
+// DELETE API end point to delete the order and its details
+
+app.delete("/orders/:orderId", async (req, res) => {
+ const orderId = req.params.orderId;
+ try {
+ // Get order items associated with the order
+ const orderItems = await pool.query(
+ "SELECT * FROM order_items WHERE order_id = $1",
+ [orderId]
+ );
+ const orderItemIds = orderItems.rows.map((item) => item.id);
+
+ // Delete the order and associated order items in a transaction
+ await pool.query("BEGIN");
+ await pool.query("DELETE FROM order_items WHERE id = ANY($1)", [
+ orderItemIds,
+ ]);
+ await pool.query("DELETE FROM orders WHERE id = $1", [orderId]);
+ await pool.query("COMMIT");
+
+ res.status(200).json({
+ message: "Order and associated order items deleted successfully.",
+ });
+ } catch (error) {
+ await pool.query("ROLLBACK");
+ console.error(error);
+ res.status(500).json({ error: "Something went wrong!" });
+ }
+});
+
+// DELETE API end point to delete customers without orders
+
+app.delete("/customers/:customerId", async (req, res) => {
+ const customerId = req.params.customerId;
+ try {
+ // Check if customer has associated orders
+ const orders = await pool.query(
+ "SELECT * FROM orders WHERE customer_id = $1",
+ [customerId]
+ );
+ if (orders.rows.length > 0) {
+ return res.status(400).json({
+ error: "Customer has associated orders and cannot be deleted.",
+ });
+ }
+
+ // Delete the customer
+ await pool.query("DELETE FROM customers WHERE id = $1", [customerId]);
+
+ res.status(200).json({ message: "Customer deleted successfully." });
+ } catch (error) {
+ console.error(error);
+ res.status(500).json({ error: "Something went wrong!" });
+ }
+});
+
+// GET API point to send customer order information
+
+app.get("/customers/:customerId/orders", async (req, res) => {
+ const customerId = req.params.customerId;
+ try {
+ const orders = await pool.query(
+ "SELECT * FROM orders WHERE customer_id = $1",
+ [customerId]
+ );
+ const result = [];
+ for (const order of orders.rows) {
+ const orderItem = await pool.query(
+ `SELECT oi.order_id, oi.quantity, pa.unit_price, p.product_name, s.supplier_name 
+ FROM order_items oi
+ JOIN product_availability pa ON oi.product_id = pa.prod_id AND oi.supplier_id = pa.supp_id
+ JOIN products p ON oi.product_id = p.id
+ JOIN suppliers s ON oi.supplier_id = s.id
+ WHERE oi.order_id = $1`,
+ [order.id]
+ );
+ result.push({
+ order_reference: order.order_reference,
+ order_date: order.order_date,
+ items: orderItem.rows,
+ });
+ }
+ res.status(200).json(result);
+ } catch (error) {
+ console.error(error);
+ res.status(500).json({ error: "Something went wrong!" });
+ }
+});
+
+app.listen(3000, () => {
+ console.log("Server is listening on port 3000");
+});