A database connection is an active communication link through which software accesses a database and submits operations. In Python, sqlite3 can open the SQLite file, create a cursor, execute a query, retrieve rows, and close the connection. section 5.3.2
Connecting a questions application
A practical workflow starts with a precise request: connect directly to SQLite without SQLAlchemy, then place the connection logic in a Questions class. The resulting code opens data/questions.db, creates a cursor, executes a query, fetches rows, and closes the connection. A later Flask entry point creates a DatabaseConnection with a with statement, passes its cursor to Questions, fetches data, and renders index.html. section 5.3.2 section 5.3.5
from flask import Flask, render_template
from app.models.database_connection import DatabaseConnection
from app.models.questions import Questions
app = Flask(__name__)
@app.route('/')
def index():
db_path = 'data/questions.db'
# Call the function and store the returned data in a variable
with DatabaseConnection(db_path) as cursor:
questions = Questions(cursor)
data = questions.fetch_data()
# Return the HTML template for the index page
return render_template('index.html', data=data)
if __name__ == "__main__":
app.run(debug=True)
Shows the complete Flask route, including the SQLite path, context-managed DatabaseConnection, Questions cursor, fetched data, template rendering, and application startup. section 5.3.5
