Validate business rules (e.g., check if the data fits within acceptable ranges or?

dates).

Example:

string customerName = txtCustomerName.Text;
if (string.IsNullOrWhiteSpace(customerName))
{

throw new ArgumentException("Customer name cannot be empty");

}

SqlCommand command = new SqlCommand("INSERT INTO Customers

(CustomerName) VALUES (@CustomerName)", connection);

command.Parameters.AddWithValue("@CustomerName", customerName);

connection.Open();

command.ExecuteNonQuery();

connection.Close();

This ensures that the CustomerName is not empty before inserting it into the database.