Glasgow Class 6 - Appolin Semegni Fotso - Module-Databases - E-Commerce-API - Week 4

.gitignore

@@ -1,2 +1,5 @@
 
 E-Commerce-API/node_modules/
+E-Commerce-API/package-lock.json
+E-Commerce-API/development.env
+

Big-Spender/readme.md

@@ -48,7 +48,7 @@ You are working with Claire and Farnoosh, who are trying to complete a missing r
 **You:** Absolutely. Here's the SQL query you need:
 
 ```sql
-INSERT YOUR QUERY HERE
+SELECT * FROM spends WHERE amount BETWEEN 30000 AND 31000;
 ```
 
 **Claire:** That's great, thanks. Hey, what about transactions that include the word 'fee' in their description?
@@ -68,39 +68,49 @@ INSERT YOUR QUERY HERE
 **You:** Then here's the query for that:
 
 ```sql
-INSERT YOUR QUERY HERE
+SELECT * FROM spends WHERE description ILIKE '%fee%';
 ```
 
 **Farnoosh:** Hi, it's me again. It turns out we also need the transactions that have the expense area of 'Better Hospital Food'. Can you help us with that one?
 
 **You:** No worries. Here's the query for that:
 
 ```sql
-INSERT YOUR QUERY HERE
+SELECT * FROM expense_areas
+FULL OUTER JOIN spends ON expense_areas.id = spends.expense_area_id
+WHERE expense_area ILIKE 'Better Hospital Food';
+
 ```
 
 **Claire:** Great, that's very helpful. How about the total amount spent for each month?
 
 **You:** You can get that by using the GROUP BY clause. Here's the query:
 
 ```sql
-CREATE YOUR QUERY HERE
+SELECT date, SUM(amount) as total_spent_per_month
+FROM spends
+GROUP BY date;
 ```
 
 **Farnoosh:** Thanks, that's really useful. We also need to know the total amount spent on each supplier. Can you help us with that?
 
 **You:** Sure thing. Here's the query for that:
 
 ```sql
-INSERT YOUR QUERY HERE
+SELECT supplier_id, SUM(amount) as total_spent_per_month
+FROM spends
+GROUP BY supplier_id;
 ```
 
 **Farnoosh:** Oh, how do I know who these suppliers are? There's only numbers here.
 
 **You:** Whoops! I gave you ids to key the totals, but let me give you names instead.
 
 ```sql
-INSERT YOUR QUERY HERE
+SELECT suppliers.id, suppliers.supplier, SUM(amount) as total_spent_per_month
+FROM suppliers
+FULL OUTER JOIN spends ON suppliers.id = spends.supplier_id
+GROUP BY suppliers.id;
 ```
 
 **Claire:** Thanks, that's really helpful. I can't quite figure out...what is the total amount spent on each of these two dates (1st March 2021 and 1st April 2021)?
@@ -112,7 +122,10 @@ INSERT YOUR QUERY HERE
 **You:** Then you need an extra clause. Here's the query:
 
 ```sql
-CREATE YOUR QUERY HERE
+SELECT date, SUM(amount) as total_spent_per_month
+FROM spends
+WHERE date BETWEEN '2021-03-01' AND '2021-04-01'
+GROUP BY date;
 ```
 
 **Farnoosh:** Fantastic. One last thing, looks like we missed something. Can we add a new transaction to the spends table with a description of 'Computer Hardware Dell' and an amount of £32,000?
@@ -124,7 +137,12 @@ CREATE YOUR QUERY HERE
 **You:** Sure thing. To confirm, the date is August 19, 2021, the transaction number is 38104091, the supplier invoice number is 3780119655, the supplier is 'Dell', the expense type is 'Hardware' and the expense area is 'IT'. Here's the query for that:
 
 ```sql
-INSERT YOUR QUERIES HERE
+INSERT INTO expense_types(expense_type) VALUES('Hardware');
+INSERT INTO expense_areas(expense_area) VALUES('IT');
+INSERT INTO suppliers(supplier) VALUES('Dell');
+INSERT INTO spends(expense_type_id, expense_area_id, supplier_id, date, transaction_no, supplier_inv_no, description, amount) VALUES(42, 46, 66,'2021-08-19', 38104091, 378011955, 'Computer Hardware Dell', 32000);
+
+
 
 ```
 

E-Commerce-API/app.js

@@ -5,4 +5,270 @@ const app = express();
 // Use environment variables instead:
 // https://www.codementor.io/@parthibakumarmurugesan/what-is-env-how-to-set-up-and-run-a-env-file-in-node-1pnyxw9yxj
 
+require("dotenv").config({ path: "./development.env" });
+const { Pool } = require("pg");
+const bodyParser = require("body-parser");
+// const CORS = require("cors");
+const port = process.env.PORT || 5000;
+// app.use(CORS());
+
+app.listen(port, () => console.log(`Listening on port ${port}`));
+app.use(express.json());
+app.use(bodyParser.urlencoded({ extended: true }));
+
+const pool = new Pool();
+
+app.get("/products", (req, res) => {
+  const allProducts = async () => {
+    try {
+      const result = await pool.query(
+        "SELECT  p.product_name as name, s.unit_price as price, s.supplier_name as supplierName FROM (SELECT * FROM suppliers FULL OUTER JOIN product_availability as pa ON suppliers.id = pa.supp_id ) as s FULL OUTER JOIN products as p ON s.prod_id = p.id"
+      );
+      res.json(result.rows);
+    } catch (err) {
+      console.log(err);
+    }
+  };
+  allProducts();
+});
+//
+app.get("/products/:name", (req, res) => {
+  const singleProduct = async () => {
+    try {
+      const result = await pool.query(
+        "SELECT  p.product_name as name, s.unit_price as price, s.supplier_name as supplierName FROM (SELECT * FROM suppliers FULL OUTER JOIN product_availability as pa ON suppliers.id = pa.supp_id ) as s FULL OUTER JOIN products as p ON s.prod_id = p.id WHERE p.product_name ILIKE $1",
+        [req.params.name]
+      );
+      res.json(result.rows);
+    } catch (err) {
+      console.log(err);
+    }
+  };
+  singleProduct();
+});
+//
+app.get("/customers/:customerId", (req, res) => {
+  const customerId = async () => {
+    try {
+      const result = await pool.query("SELECT * FROM customers WHERE id = $1", [
+        req.params.customerId,
+      ]);
+      res.json(result.rows);
+    } catch (err) {
+      console.log(err);
+    }
+  };
+  customerId();
+});
+//
+app.post("/customers", (req, res) => {
+  const newCustomer = async () => {
+    try {
+      await pool.query(
+        "INSERT INTO customers (name, address, city, country) VALUES($1, $2, $3, $4)",
+        [req.body.name, req.body.address, req.body.city, req.body.country]
+      );
+      const result = await pool.query(
+        "SELECT * FROM customers WHERE name = $1",
+        [req.body.name]
+      );
+      res.json(result.rows);
+    } catch (err) {
+      console.log(err);
+    }
+  };
+  newCustomer();
+});
+//
+app.post("/products", (req, res) => {
+  const newProduct = async () => {
+    try {
+      await pool.query("INSERT INTO products (product_name) VALUES($1)", [
+        req.body.name,
+      ]);
+      const result = await pool.query(
+        "SELECT * FROM products WHERE product_name = $1",
+        [req.body.name]
+      );
+      res.json(result.rows);
+    } catch (err) {
+      console.log(err);
+    }
+  };
+  newProduct();
+});
+//
+app.post("/availability", (req, res) => {
+  const productAvailability = async () => {
+    try {
+      let unitPrice = await pool.query(
+        "INSERT INTO product_availability (prod_id, supp_id, unit_price) VALUES($1, $2, $3)",
+        [
+          req.body.prodId,
+          req.body.suppId,
+          req.body.unitPrice < 0
+            ? "Need a positive integer as unit price"
+            : req.body.unitPrice,
+        ]
+      );
+      const result = await pool.query(
+        "SELECT * FROM product_availability WHERE prod_id = $1 AND supp_id = $2",
+        [req.body.prodId, req.body.suppId]
+      );
+      res.json(result.rows);
+    } catch (err) {
+      console.log(err);
+    }
+  };
+  productAvailability();
+});
+//
+app.post("/customers/:customerId/orders", (req, res) => {
+  const newOrder = async () => {
+    try {
+      const checkCustomerId = await pool.query(
+        "SELECT id FROM customers WHERE id = $1",
+        [req.params.customerId]
+      );
+      let customerId =
+        checkCustomerId.rows.length !== 0
+          ? checkCustomerId.rows[0].id
+          : res.json("Customer ID does not exist");
+      await pool.query(
+        "INSERT INTO orders (order_date, order_reference, customer_id) VALUES($1, $2, $3)",
+        [req.body.orderDate, req.body.orderReference, customerId]
+      );
+      const result = await pool.query(
+        "SELECT * FROM orders WHERE order_reference = $1",
+        [req.body.orderReference]
+      );
+      res.json(result.rows);
+    } catch (err) {
+      console.log(err);
+    }
+  };
+  newOrder();
+});
+//
+app.post("/customers/:customerId", (req, res) => {
+  const customerUpdate = async () => {
+    try {
+      const checkCustomerId = await pool.query(
+        "SELECT id FROM customers WHERE id = $1",
+        [req.params.customerId]
+      );
+      let customerId =
+        checkCustomerId.rows.length !== 0
+          ? checkCustomerId.rows[0].id
+          : res.json("Customer ID does not exist");
+      await pool.query(
+        "UPDATE customers SET name = $1, address = $2, city = $3, country = $4 WHERE id = $5",
+        [
+          req.body.name,
+          req.body.address,
+          req.body.city,
+          req.body.country,
+          customerId,
+        ]
+      );
+      const result = await pool.query("SELECT * FROM customers WHERE id = $1", [
+        req.params.customerId,
+      ]);
+      res.json(result.rows);
+    } catch (err) {
+      console.log(err);
+    }
+  };
+  customerUpdate();
+});
+//
+app.delete("/orders/:orderId", (req, res) => {
+  const deleteCustomer = async () => {
+    try {
+      const checkOrderId = await pool.query(
+        "SELECT id FROM orders WHERE id = $1",
+        [req.params.orderId]
+      );
+      let orderId =
+        checkOrderId.rows.length !== 0
+          ? checkOrderId.rows[0].id
+          : res.json("Order ID does not exist");
+      const result = await pool.query("DELETE FROM orders WHERE id = $1", [
+        orderId,
+      ]);
+
+      res.json(result);
+    } catch (err) {
+      console.log(err);
+    }
+  };
+  deleteCustomer();
+});
+//
+app.delete("/customers/:customerId", (req, res) => {
+  const deleteCustomer = async () => {
+    try {
+      //Checking if a customer exist
+      const checkCustomerId = await pool.query(
+        "SELECT id FROM customers WHERE id = $1",
+        [req.params.customerId]
+      );
+      let customerId =
+        checkCustomerId.rows.length !== 0
+          ? checkCustomerId.rows[0].id
+          : res.json("Customer ID does not exist");
+      //Checking if a customer placed an order
+      const checkOrderId = await pool.query(
+        "SELECT customer_id FROM orders WHERE customer_id = $1",
+        [customerId]
+      );
+      let orderId =
+        checkOrderId.rows.length !== 0 ? res.json("Order exists") : customerId;
+      //Delete customer
+      const result = await pool.query("DELETE FROM customers WHERE id = $1", [
+        orderId,
+      ]);
+
+      res.json(result);
+    } catch (err) {
+      console.log(err);
+    }
+  };
+  deleteCustomer();
+});
+//
+app.get("/customers/:customerId/orders", (req, res) => {
+  const newOrder = async () => {
+    try {
+      //Checking if a customer exist
+      const checkCustomerId = await pool.query(
+        "SELECT id FROM customers WHERE id = $1",
+        [req.params.customerId]
+      );
+      let customerId =
+        checkCustomerId.rows.length !== 0
+          ? checkCustomerId.rows[0].id
+          : res.json("Customer ID does not exist");
+      //Checking if a customer placed an order
+      const checkOrderId = await pool.query(
+        "SELECT customer_id FROM orders WHERE customer_id = $1",
+        [customerId]
+      );
+      let orderId =
+        checkOrderId.rows.length !== 0
+          ? customerId
+          : res.json("Order does not exist");
+      // Load all the orders for one customer
+      const result = await pool.query(
+        "SELECT c.name, o.order_reference, o.order_date, o.product_name, o.supplier_name, o.unit_price, o.quantity FROM (SELECT * FROM (SELECT * FROM (SELECT * FROM (SELECT * FROM suppliers as s FULL OUTER JOIN product_availability as pa ON s.id = pa.supp_id) as pa FULL OUTER JOIN products as p ON pa.prod_id = p.id) as p FULL OUTER JOIN order_items as i ON p.prod_id = i.product_id) as i FULL OUTER JOIN orders as o ON i.order_id = o.id) as o FULL OUTER JOIN customers as c ON o.customer_id = c.id WHERE c.id = $1;",
+        [orderId]
+      );
+      res.json(result.rows);
+    } catch (err) {
+      console.log(err);
+    }
+  };
+  newOrder();
+});
+//
 module.exports = app;

E-Commerce-API/package.json

@@ -4,7 +4,7 @@
   "description": "API for the CYF ecommerce application",
   "main": "index.js",
   "scripts": {
-    "start": "node app.js",
+    "start": "nodemon app.js",
     "test": "jest"
   },
   "keywords": [
@@ -16,7 +16,11 @@
   "author": "CYF",
   "license": "CC-BY-4-0",
   "dependencies": {
-    "express": "^4.17.1"
+    "cors": "^2.8.5",
+    "dotenv": "^16.3.1",
+    "express": "^4.17.1",
+    "nodemon": "^3.0.1",
+    "pg": "^8.11.3"
   },
   "devDependencies": {
     "jest": "^27.2.5",