Database query C# Exercise - C# Programming Course

// Importing necessary namespaces for SQLite operations and basic functionalities
using System; // For basic functionalities like Console and Exception handling
using System.Data.SQLite; // For SQLite operations

// Define a class to handle the database operations for querying the books
class BookDataQuery
{
    private string connectionString; // Connection string to connect to the SQLite database

    // Constructor to initialize the connection string
    public BookDataQuery(string connectionString)
    {
        this.connectionString = connectionString; // Store the connection string
    }

    // Method to display all books stored in the SQLite database
    public void DisplayBooks()
    {
        // SQL query to select all books from the Books table
        string query = "SELECT * FROM Books;";

        // Establish a connection to the SQLite database
        using (SQLiteConnection conn = new SQLiteConnection(connectionString))
        {
            // Open the connection
            conn.Open();

            // Create a SQLiteCommand to execute the query
            using (SQLiteCommand cmd = new SQLiteCommand(query, conn))
            {
                // Execute the query and get a SQLiteDataReader to read the results
                using (SQLiteDataReader reader = cmd.ExecuteReader())
                {
                    // Print each book from the result set
                    Console.WriteLine("Books in the database:");
                    Console.WriteLine("-------------------------------------");
                    while (reader.Read())
                    {
                        // Display each book's data
                        Console.WriteLine($"ID: {reader["Id"]}");
                        Console.WriteLine($"Title: {reader["Title"]}");
                        Console.WriteLine($"Author: {reader["Author"]}");
                        Console.WriteLine($"Genre: {reader["Genre"]}");
                        Console.WriteLine($"Summary: {reader["Summary"]}");
                        Console.WriteLine("-------------------------------------");
                    }
                }
            }
        }
    }
}

// Main class to demonstrate the functionality
class Program
{
    static void Main(string[] args)
    {
        // Connection string to the SQLite database (SQLite creates the database file if it doesn't exist)
        string connectionString = "Data Source=Books.db;Version=3;";

        // Create an instance of BookDataQuery to handle database query operations
        BookDataQuery query = new BookDataQuery(connectionString);

        // Display all books stored in the database
        query.DisplayBooks();
    }
}