From 2a6f6c61018d5b5175fc3e3d08ccd46551004149 Mon Sep 17 00:00:00 2001
From: Mati-guty <66220729+Matias023@users.noreply.github.com>
Date: Mon, 5 Jan 2026 23:49:12 +0000
Subject: [PATCH] go

---
 .env.example |  6 ++--
 src/app.py   | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 80 insertions(+), 3 deletions(-)

diff --git a/.env.example b/.env.example
index 81f0cd9a7..6e7a5e7c9 100644
--- a/.env.example
+++ b/.env.example
@@ -1,5 +1,5 @@
-DB_USER='ejemplo'
-DB_PASSWORD='ejemplo'
+DB_USER='matias'
+DB_PASSWORD='onlyone182x'
 DB_PORT= 3306
 DB_HOST='localhost'
-DB_NAME='ejemplo'
\ No newline at end of file
+DB_NAME='db'
diff --git a/src/app.py b/src/app.py
index e5d7b62ed..ae6425233 100644
--- a/src/app.py
+++ b/src/app.py
@@ -4,12 +4,89 @@
 from dotenv import load_dotenv
 
 # Load environment variables
+load_dotenv()
 
 # 1) Connect to the database with SQLAlchemy
 
+def connect():
+    global engine
+    try:
+        connection_string = f"postgresql://{os.getenv('DB_USER')}:{os.getenv('DB_PASSWORD')}@{os.getenv('DB_HOST')}/{os.getenv('DB_NAME')}"
+        print("Starting the connection...")
+        engine = create_engine(connection_string, isolation_level="AUTOCOMMIT") 
+        engine.connect()
+        print("Connected successfully!")
+        return engine
+    except Exception as e:
+        print(f"Error connecting to the database: {e}")
+        return None
+
+engine = connect()
+
+if engine is None:
+    exit() 
+
 # 2) Create the tables
+with engine.connect() as connection:
+    connection.execute(text("""
+    CREATE TABLE IF NOT EXISTS publishers (
+        publisher_id SERIAL PRIMARY KEY,
+        name VARCHAR(255) NOT NULL
+    );
+
+    CREATE TABLE IF NOT EXISTS authors (
+        author_id SERIAL PRIMARY KEY,
+        first_name VARCHAR(100) NOT NULL,
+        middle_name VARCHAR(50) NULL,
+        last_name VARCHAR(100) NULL
+    );
+
+    CREATE TABLE IF NOT EXISTS books (
+        book_id SERIAL PRIMARY KEY,
+        title VARCHAR(255) NOT NULL,
+        total_pages INT NULL,
+        rating DECIMAL(4, 2) NULL,
+        isbn VARCHAR(13) NULL,
+        published_date DATE,
+        publisher_id INT NULL,
+        CONSTRAINT fk_publisher FOREIGN KEY (publisher_id) REFERENCES publishers(publisher_id) ON DELETE SET NULL
+    );
+
+    CREATE TABLE IF NOT EXISTS book_authors (
+        book_id INT NOT NULL,
+        author_id INT NOT NULL,
+        PRIMARY KEY (book_id, author_id),
+        CONSTRAINT fk_book FOREIGN KEY (book_id) REFERENCES books(book_id) ON DELETE CASCADE,
+        CONSTRAINT fk_author FOREIGN KEY (author_id) REFERENCES authors(author_id) ON DELETE CASCADE
+    );
+    """))
 
 # 3) Insert data
+with engine.connect() as connection:
+    connection.execute(text("""
+    INSERT INTO publishers (publisher_id, name) VALUES
+        (1, 'O Reilly Media'),
+        (2, 'A Book Apart'),
+        (3, 'A K PETERS'),
+        (4, 'Academic Press'),
+        (5, 'Addison Wesley'),
+        (6, 'Albert&Sweigart'),
+        (7, 'Alfred A. Knopf')
+    ON CONFLICT (publisher_id) DO NOTHING;
+
+    INSERT INTO authors (author_id, first_name, middle_name, last_name) VALUES
+        (1, 'Merritt', NULL, 'Eric'),
+        (2, 'Linda', NULL, 'Mui'),
+        (3, 'Alecos', NULL, 'Papadatos'),
+        (4, 'Anthony', NULL, 'Molinaro'),
+        (5, 'David', NULL, 'Cronin'),
+        (6, 'Richard', NULL, 'Blum'),
+        (7, 'Yuval', 'Noah', 'Harari'),
+        (8, 'Paul', NULL, 'Albitz')
+    ON CONFLICT (author_id) DO NOTHING;
+    """))
 
 # 4) Use Pandas to read and display a table
+df = pd.read_sql("SELECT * FROM publishers;", engine)
+print(df)