Environment patches

.vscode/settings.json

@@ -2,5 +2,8 @@
     "workbench.startupEditor": "readme",
     "workbench.editorAssociations": {
         "*.md": "vscode.markdown.preview.editor"
-    }
+    },
+    "githubPullRequests.ignoredPullRequestBranches": [
+        "main"
+    ]
 }

requirements.txt

@@ -1,6 +1,6 @@
 # Base ----------------------------------------
-sqlalchemy
-pandas
+sqlalchemy==1.4.0
+pandas==2.1.4
 python-dotenv==0.20.0
 psycopg2-binary==2.9.3
 

src/app.py

@@ -7,13 +7,99 @@
 load_dotenv()
 
 # 1) Connect to the database here using the SQLAlchemy's create_engine function
-connection_string = f"postgresql://{os.getenv('DB_USER')}:{os.getenv('DB_PASSWORD')}@{os.getenv('DB_HOST')}/{os.getenv('DB_NAME')}"
-engine = create_engine(connection_string).execution_options(autocommit=True)
+connection_string=f"postgresql://{os.getenv('DB_USER')}:{os.getenv('DB_PASSWORD')}@{os.getenv('DB_HOST')}/{os.getenv('DB_NAME')}"
+engine=create_engine(connection_string).execution_options(autocommit=True)
 engine.connect()
 
-# 2) Execute the SQL sentences to create your tables using the SQLAlchemy's execute function
+def create_table(table_name: str, query: str) -> None:
+    '''Function to create SQL table if it
+    does not exist.'''
+
+    if not engine.dialect.has_table(engine, table_name):
+        engine.execute(query)
+        print(f'Created {table_name} table')
+
+    else:
+        print(f'Tabel {table_name} exists')
+
+tables={
+'publishers': """CREATE TABLE publishers(
+    publisher_id INT NOT NULL,
+    name VARCHAR(255) NOT NULL,
+    PRIMARY KEY(publisher_id)
+);""",
+'authors': """CREATE TABLE authors(
+    author_id INT NOT NULL,
+    first_name VARCHAR(100) NOT NULL,
+    middle_name VARCHAR(50) NULL,
+    last_name VARCHAR(100) NULL,
+    PRIMARY KEY(author_id)
+);""",
+'books': """CREATE TABLE books(
+    book_id INT NOT NULL,
+    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,
+    PRIMARY KEY(book_id),
+    CONSTRAINT fk_publisher FOREIGN KEY(publisher_id) REFERENCES publishers(publisher_id)
+);""",
+'book_authors':"""CREATE TABLE 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
+);"""
+}
+
+for table_name, query in tables.items():
+    create_table(table_name, query)
 
 # 3) Execute the SQL sentences to insert your data using the SQLAlchemy's execute function
+engine.execute("""
+INSERT INTO publishers(publisher_id, name) VALUES (1, 'O Reilly Media') ON CONFLICT (publisher_id) DO NOTHING;
+INSERT INTO publishers(publisher_id, name) VALUES (2, 'A Book Apart') ON CONFLICT (publisher_id) DO NOTHING;
+INSERT INTO publishers(publisher_id, name) VALUES (3, 'A K PETERS') ON CONFLICT (publisher_id) DO NOTHING;
+INSERT INTO publishers(publisher_id, name) VALUES (4, 'Academic Press') ON CONFLICT (publisher_id) DO NOTHING;
+INSERT INTO publishers(publisher_id, name) VALUES (5, 'Addison Wesley') ON CONFLICT (publisher_id) DO NOTHING;
+INSERT INTO publishers(publisher_id, name) VALUES (6, 'Albert&Sweigart') ON CONFLICT (publisher_id) DO NOTHING;
+INSERT INTO publishers(publisher_id, name) VALUES (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') ON CONFLICT (author_id) DO NOTHING;
+INSERT INTO authors (author_id, first_name, middle_name, last_name) VALUES (2, 'Linda', null, 'Mui') ON CONFLICT (author_id) DO NOTHING;
+INSERT INTO authors (author_id, first_name, middle_name, last_name) VALUES (3, 'Alecos', null, 'Papadatos') ON CONFLICT (author_id) DO NOTHING;
+INSERT INTO authors (author_id, first_name, middle_name, last_name) VALUES (4, 'Anthony', null, 'Molinaro') ON CONFLICT (author_id) DO NOTHING;
+INSERT INTO authors (author_id, first_name, middle_name, last_name) VALUES (5, 'David', null, 'Cronin') ON CONFLICT (author_id) DO NOTHING;
+INSERT INTO authors (author_id, first_name, middle_name, last_name) VALUES (6, 'Richard', null, 'Blum') ON CONFLICT (author_id) DO NOTHING;
+INSERT INTO authors (author_id, first_name, middle_name, last_name) VALUES (7, 'Yuval', 'Noah', 'Harari') ON CONFLICT (author_id) DO NOTHING;
+INSERT INTO authors (author_id, first_name, middle_name, last_name) VALUES (8, 'Paul', null, 'Albitz') ON CONFLICT (author_id) DO NOTHING;
+
+INSERT INTO books (book_id, title, total_pages, rating, isbn, published_date, publisher_id) VALUES (1, 'Lean Software Development: An Agile Toolkit', 240, 4.17, '9780320000000', '2003-05-18', 5) ON CONFLICT (book_id) DO NOTHING;
+INSERT INTO books (book_id, title, total_pages, rating, isbn, published_date, publisher_id) VALUES (2, 'Facing the Intelligence Explosion', 91, 3.87, null, '2013-02-01', 7) ON CONFLICT (book_id) DO NOTHING;
+INSERT INTO books (book_id, title, total_pages, rating, isbn, published_date, publisher_id) VALUES (3, 'Scala in Action', 419, 3.74, '9781940000000', '2013-04-10', 1) ON CONFLICT (book_id) DO NOTHING;
+INSERT INTO books (book_id, title, total_pages, rating, isbn, published_date, publisher_id) VALUES (4, 'Patterns of Software: Tales from the Software Community', 256, 3.84, '9780200000000', '1996-08-15', 1) ON CONFLICT (book_id) DO NOTHING;
+INSERT INTO books (book_id, title, total_pages, rating, isbn, published_date, publisher_id) VALUES (5, 'Anatomy Of LISP', 446, 4.43, '9780070000000', '1978-01-01', 3) ON CONFLICT (book_id) DO NOTHING;
+INSERT INTO books (book_id, title, total_pages, rating, isbn, published_date, publisher_id) VALUES (6, 'Computing machinery and intelligence', 24, 4.17, null, '2009-03-22', 4) ON CONFLICT (book_id) DO NOTHING;
+INSERT INTO books (book_id, title, total_pages, rating, isbn, published_date, publisher_id) VALUES (7, 'XML: Visual QuickStart Guide', 269, 3.66, '9780320000000', '2009-01-01', 5) ON CONFLICT (book_id) DO NOTHING;
+INSERT INTO books (book_id, title, total_pages, rating, isbn, published_date, publisher_id) VALUES (8, 'SQL Cookbook', 595, 3.95, '9780600000000', '2005-12-01', 7) ON CONFLICT (book_id) DO NOTHING;
+INSERT INTO books (book_id, title, total_pages, rating, isbn, published_date, publisher_id) VALUES (9, 'The Apollo Guidance Computer: Architecture And Operation (Springer Praxis Books / Space Exploration)', 439, 4.29, '9781440000000', '2010-07-01', 6) ON CONFLICT (book_id) DO NOTHING;
+INSERT INTO books (book_id, title, total_pages, rating, isbn, published_date, publisher_id) VALUES (10, 'Minds and Computers: An Introduction to the Philosophy of Artificial Intelligence', 222, 3.54, '9780750000000', '2007-02-13', 7) ON CONFLICT (book_id) DO NOTHING;
 
+INSERT INTO book_authors (book_id, author_id) VALUES (1, 1);
+INSERT INTO book_authors (book_id, author_id) VALUES (2, 8);
+INSERT INTO book_authors (book_id, author_id) VALUES (3, 7);
+INSERT INTO book_authors (book_id, author_id) VALUES (4, 6);
+INSERT INTO book_authors (book_id, author_id) VALUES (5, 5);
+INSERT INTO book_authors (book_id, author_id) VALUES (6, 4);
+INSERT INTO book_authors (book_id, author_id) VALUES (7, 3);
+INSERT INTO book_authors (book_id, author_id) VALUES (8, 2);
+INSERT INTO book_authors (book_id, author_id) VALUES (9, 4);
+INSERT INTO book_authors (book_id, author_id) VALUES (10, 1);
+""")
 
 # 4) Use pandas to print one of the tables as dataframes using read_sql function
+result_dataFrame=pd.read_sql("Select * from publishers;", engine)
+print(result_dataFrame)

src/solution.py

@@ -45,7 +45,7 @@
     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) Execute the SQL sentences to insert your data using the SQLAlchemy's execute function
 engine.execute("""

src/start_db.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+# Starts posgreSQL service, creates gitpod user and creates database 'sample_db'
+sudo service postgresql start
+psql -U postgres -c "CREATE USER gitpod;"
+psql -U postgres -c "CREATE DATABASE sample_db OWNER gitpod;"