basic.rb (3-73)
- require statements @3
- DataAccess @8 # Data access layer module
  - DatabaseManager @10 # Manages database connections and queries
    - initialize (connection_string) @14
       def initialize(connection_string)
         @connection_string = connection_string
         @connection = nil
       …
    - connect () @20 # Establish database connection
       def connect
         puts "Connecting to #{@connection_string}"
       …
    - disconnect () @25 # Close database connection
       def disconnect
         @connection&.close
       …
    - query (sql) @30 # Execute a SQL query
       def query(sql)
         …
    - self.create_default () @35 [class] # Class method for creating a default instance
       def self.create_default
         new("postgresql://localhost/mydb")
       …
- UserService @42 # Handles user-related operations
  - initialize (db) @43
     def initialize(db)
       @db = db
     …
  - create_user (username, email) @48 # Create a new user
     def create_user(username, email)
       …
  - get_user (user_id) @53 # Retrieve user by ID
     def get_user(user_id)
       …
  - delete_user (user_id) @58 # Delete a user
     def delete_user(user_id)
       …
- validate_email (email) @64 # Validate email format
   def validate_email(email)
     email.include?('@')
   …
- main () @69 # Main entry point
   def main
     db = DataAccess::DatabaseManager.create_default
     service = UserService.new(db)
     puts "Application started"
   …
