asp.net存储数据到数据库

string query = "SELECT * FROM Users WHERE Username = @username AND Password = @password";
using (SqlConnection connection = new SqlConnection(connectionString))
{
    SqlCommand command = new SqlCommand(query, connection);
    command.Parameters.AddWithValue("@username", username);
    command.Parameters.AddWithValue("@password", password);
    connection.Open();
    SqlDataReader reader = command.ExecuteReader();
    // 处理结果
}

using (SqlConnection connection = new SqlConnection(connectionString))
{
    connection.Open();
    SqlTransaction transaction = connection.BeginTransaction();
    try
    {
        SqlCommand command = new SqlCommand("UPDATE Table SET Column = @value WHERE Id = @id", connection, transaction);
        command.Parameters.AddWithValue("@value", newValue);
        command.Parameters.AddWithValue("@id", id);
        command.ExecuteNonQuery();
        transaction.Commit();
    }
    catch (Exception)
    {
        transaction.Rollback();
        throw;
    }
}