Ahmad_w3_database_assignment

Week3/EX3-injection.js

@@ -0,0 +1,27 @@
+const client = require('pg');
+
+const client = new Client({
+host: "localhost",
+user: "hyfuser",
+password: "hyfpass",
+database: "world",
+port: 5432,
+});
+
+client.connect();
+async function getPopulation(countryTable, name, code) {
+const sql = `
+SELECT population
+FROM ${countryTable}
+WHERE name = $1 AND code = $2
+`;
+const values = [name, code];
+
+const result = await client.query(sql, values);
+
+if (!result || result.rows.length === 0) {
+throw new Error('Not found');
+}
+
+return result.rows[0].population;
+}

Week3/Ex1-Normalization.sql

@@ -0,0 +1,45 @@
+-- 3NF Normalized Schema
+
+
+CREATE TABLE members (
+    member_id INT PRIMARY KEY,
+    member_name VARCHAR(100) NOT NULL,
+    member_address VARCHAR(200) NOT NULL
+);
+
+CREATE TABLE venues (
+    venue_code VARCHAR(10) PRIMARY KEY,
+    venue_description VARCHAR(200) NOT NULL
+);
+
+
+CREATE TABLE dinners (
+    dinner_id VARCHAR(20) PRIMARY KEY,
+    dinner_date DATE NOT NULL,
+    venue_code VARCHAR(10) NOT NULL,
+    FOREIGN KEY (venue_code) REFERENCES venues(venue_code)
+);
+
+
+CREATE TABLE food (
+    food_code VARCHAR(10) PRIMARY KEY,
+    food_description VARCHAR(100) NOT NULL
+);
+
+
+CREATE TABLE dinner_food (
+    dinner_id VARCHAR(20),
+    food_code VARCHAR(10),
+    PRIMARY KEY (dinner_id, food_code),
+    FOREIGN KEY (dinner_id) REFERENCES dinners(dinner_id),
+    FOREIGN KEY (food_code) REFERENCES food(food_code)
+);
+
+
+CREATE TABLE member_dinner (
+    member_id INT,
+    dinner_id VARCHAR(20),
+    PRIMARY KEY (member_id, dinner_id),
+    FOREIGN KEY (member_id) REFERENCES members(member_id),
+    FOREIGN KEY (dinner_id) REFERENCES dinners(dinner_id)
+);

Week3/Ex2-Transactions/create-tables.js

@@ -0,0 +1,31 @@
+import client from "./database.js";
+
+async function createTables() {
+await client.connect();
+
+try {
+await client.query(`
+    CREATE TABLE IF NOT EXISTS account (
+    account_number INT PRIMARY KEY,
+    balance NUMERIC(12,2) NOT NULL
+    );
+
+    CREATE TABLE IF NOT EXISTS account_changes (
+    change_number SERIAL PRIMARY KEY,
+    account_number INT NOT NULL,
+    amount NUMERIC(12,2) NOT NULL,
+    changed_date TIMESTAMP DEFAULT NOW(),
+    remark TEXT,
+    FOREIGN KEY (account_number) REFERENCES account(account_number)
+    );
+`);
+
+console.log("Tables created successfully");
+} catch (err) {
+console.error("Error creating tables:", err);
+} finally {
+await client.end();
+}
+}
+
+createTables();

Week3/Ex2-Transactions/database.js

@@ -0,0 +1,11 @@
+import pg from "pg";
+
+const client = new pg.Client({
+host: "localhost",
+port: 5432,
+user: "hyfuser",
+password: "hyfpassword",
+database: "bankdb",
+});
+
+export default client;

Week3/Ex2-Transactions/insert-values.js

@@ -0,0 +1,24 @@
+import client from "./database.js";
+
+async function insertValues() {
+await client.connect();
+
+try {
+await client.query(`
+    INSERT INTO account (account_number, balance)
+    VALUES
+    (101, 5000),
+    (102, 3000)
+    ON CONFLICT (account_number) DO NOTHING;
+`);
+
+console.log("Sample accounts inserted");
+
+} catch (err) {
+console.error("Error inserting values:", err);
+} finally {
+await client.end();
+}
+}
+
+insertValues();

Week3/Ex2-Transactions/transaction.js

@@ -0,0 +1,49 @@
+import client from "./database.js";
+
+async function doTransaction() {
+await client.connect();
+
+try {
+await client.query("BEGIN");
+
+const amount = 1000;
+const fromAcc = 101;
+const toAcc = 102;
+
+// 1. Subtract from account 101
+await client.query(
+    `UPDATE account SET balance = balance - $1 WHERE account_number = $2`,
+    [amount, fromAcc]
+);
+
+await client.query(
+    `INSERT INTO account_changes (account_number, amount, remark)
+    VALUES ($1, $2, 'Transfer to 102')`,
+    [fromAcc, -amount]
+);
+
+// 2. Add to account 102
+await client.query(
+    `UPDATE account SET balance = balance + $1 WHERE account_number = $2`,
+    [amount, toAcc]
+);
+
+await client.query(
+    `INSERT INTO account_changes (account_number, amount, remark)
+    VALUES ($1, $2, 'Transfer from 101')`,
+    [toAcc, amount]
+);
+
+// If everything is OK → commit
+await client.query("COMMIT");
+console.log("Transaction completed successfully");
+
+} catch (err) {
+console.error("Transaction failed:", err);
+await client.query("ROLLBACK");
+} finally {
+await client.end();
+}
+}
+
+doTransaction();

Week3/homework/mongodb/.env.example

@@ -4,4 +4,4 @@
 # - look up how to connect to your database in atlas, there is a nice `connect` button that will help you out
 # - fill in the link to your new database. Make sure the database is `databaseWeek3`!
 
-MONGODB_URL=mongodb+srv://<username>:<password>@<cluster>/databaseWeek3?retryWrites=true&w=majority
+MONGODB_URL=mongodb+srv://asaadeddin87_db_user:<password>@<cluster_url>/databaseWeek3

Week3/homework/mongodb/.gitignore

@@ -0,0 +1,2 @@
+.env
+node_modules/

Week3/homework/mongodb/index.js

@@ -1,104 +1,81 @@
+require('dotenv').config();
 const { MongoClient, ServerApiVersion } = require("mongodb");
-
 const { seedDatabase } = require("./seedDatabase.js");
 
 async function createEpisodeExercise(client) {
-  /**
-   * We forgot to add the last episode of season 9. It has this information:
-   *
-   * episode: S09E13
-   * title: MOUNTAIN HIDE-AWAY
-   * elements: ["CIRRUS", "CLOUDS", "CONIFER", "DECIDIOUS", "GRASS", "MOUNTAIN", "MOUNTAINS", "RIVER", "SNOWY_MOUNTAIN", "TREE", "TREES"]
-   */
+  const collection = client.db("databaseWeek3").collection("bob_ross_episodes");
+
+  const newEpisode = {
+    episode: "S09E13",
+    title: "MOUNTAIN HIDE-AWAY",
+    elements: ["CIRRUS", "CLOUDS", "CONIFER", "DECIDUOUS", "GRASS", "MOUNTAIN", "MOUNTAINS", "RIVER", "SNOWY_MOUNTAIN", "TREE", "TREES"]
+  };
 
-  // Write code that will add this to the collection!
+  const result = await collection.insertOne(newEpisode);
 
   console.log(
-    `Created season 9 episode 13 and the document got the id ${"TODO: fill in variable here"}`
+    `Created season 9 episode 13 and the document got the id ${result.insertedId}`
   );
 }
 
 async function findEpisodesExercises(client) {
-  /**
-   * Complete the following exercises.
-   * The comments indicate what to do and what the result should be!
-   */
-
-  // Find the title of episode 2 in season 2 [Should be: WINTER SUN]
-
-  console.log(
-    `The title of episode 2 in season 2 is ${"TODO: fill in variable here"}`
-  );
+  const collection = client.db("databaseWeek3").collection("bob_ross_episodes");
 
-  // Find the season and episode number of the episode called "BLACK RIVER" [Should be: S02E06]
+  // Title of episode 2 in season 2
+  const ep2s2 = await collection.findOne({ episode: "S02E02" });
+  console.log(`The title of episode 2 in season 2 is ${ep2s2.title}`);
 
-  console.log(
-    `The season and episode number of the "BLACK RIVER" episode is ${"TODO: fill in variable here"}`
-  );
-
-  // Find all of the episode titles where Bob Ross painted a CLIFF [Should be: NIGHT LIGHT, EVENING SEASCAPE, SURF'S UP, CLIFFSIDE, BY THE SEA, DEEP WILDERNESS HOME, CRIMSON TIDE, GRACEFUL WATERFALL]
-
-  console.log(
-    `The episodes that Bob Ross painted a CLIFF are ${"TODO: fill in variable here"}`
-  );
+  // Season and episode of "BLACK RIVER"
+  const blackRiver = await collection.findOne({ title: "BLACK RIVER" });
+  console.log(`The season and episode number of the "BLACK RIVER" episode is ${blackRiver.episode}`);
 
-  // Find all of the episode titles where Bob Ross painted a CLIFF and a LIGHTHOUSE [Should be: NIGHT LIGHT]
+  // Episodes with CLIFF
+  const cliffEpisodes = await collection.find({ elements: "CLIFF" }).toArray();
+  console.log(`The episodes that Bob Ross painted a CLIFF are ${cliffEpisodes.map(e => e.title).join(", ")}`);
 
-  console.log(
-    `The episodes that Bob Ross painted a CLIFF and a LIGHTHOUSE are ${"TODO: fill in variable here"}`
-  );
+  // Episodes with CLIFF and LIGHTHOUSE
+  const cliffLighthouse = await collection.find({ elements: { $all: ["CLIFF", "LIGHTHOUSE"] } }).toArray();
+  console.log(`The episodes that Bob Ross painted a CLIFF and a LIGHTHOUSE are ${cliffLighthouse.map(e => e.title).join(", ")}`);
 }
 
 async function updateEpisodeExercises(client) {
-  /**
-   * There are some problems in the initial data that was filled in.
-   * Let's use update functions to update this information.
-   *
-   * Note: do NOT change the data.json file
-   */
+  const collection = client.db("databaseWeek3").collection("bob_ross_episodes");
 
-  // Episode 13 in season 30 should be called BLUE RIDGE FALLS, yet it is called BLUE RIDGE FALLERS now. Fix that
-
-  console.log(
-    `Ran a command to update episode 13 in season 30 and it updated ${"TODO: fill in variable here"} episodes`
+  // Fix season 30 episode 13 title
+  const updateTitle = await collection.updateOne(
+    { episode: "S30E13" },
+    { $set: { title: "BLUE RIDGE FALLS" } }
   );
+  console.log(`Ran a command to update episode 13 in season 30 and it updated ${updateTitle.modifiedCount} episodes`);
 
-  // Unfortunately we made a mistake in the arrays and the element type called 'BUSHES' should actually be 'BUSH' as sometimes only one bush was painted.
-  // Update all of the documents in the collection that have `BUSHES` in the elements array to now have `BUSH`
-  // It should update 120 episodes!
-
-  console.log(
-    `Ran a command to update all the BUSHES to BUSH and it updated ${"TODO: fill in variable here"} episodes`
+  // Replace BUSHES with BUSH
+  const updateBushes = await collection.updateMany(
+    { elements: "BUSHES" },
+    { $set: { "elements.$": "BUSH" } }
   );
+  console.log(`Ran a command to update all the BUSHES to BUSH and it updated ${updateBushes.modifiedCount} episodes`);
 }
 
 async function deleteEpisodeExercise(client) {
-  /**
-   * It seems an errand episode has gotten into our data.
-   * This is episode 14 in season 31. Please remove it and verify that it has been removed!
-   */
+  const collection = client.db("databaseWeek3").collection("bob_ross_episodes");
 
-  console.log(
-    `Ran a command to delete episode and it deleted ${"TODO: fill in variable here"} episodes`
-  );
+  const result = await collection.deleteOne({ episode: "S31E14" });
+  console.log(`Ran a command to delete episode and it deleted ${result.deletedCount} episodes`);
 }
 
 async function main() {
-  if (process.env.MONGODB_URL == null) {
-    throw Error(
-      `You did not set up the environment variables correctly. Did you create a '.env' file and add a package to create it?`
-    );
+  if (!process.env.MONGODB_URL) {
+    throw new Error("Please set MONGODB_URL in your .env file");
   }
+
   const client = new MongoClient(process.env.MONGODB_URL, {
-    useNewUrlParser: true,
-    useUnifiedTopology: true,
-    serverApi: ServerApiVersion.v1,
+    serverApi: ServerApiVersion.v1
   });
 
   try {
     await client.connect();
 
-    // Seed our database
+    // Seed database
     await seedDatabase(client);
 
     // CREATE
@@ -112,11 +89,11 @@ async function main() {
 
     // DELETE
     await deleteEpisodeExercise(client);
+
   } catch (err) {
     console.error(err);
   } finally {
-    // Always close the connection at the end
-    client.close();
+    await client.close();
   }
 }