C#脚本不会将行更新/插入SQL DB

我正在运行用DSharpPlus编写的Discord机器人。我正在调试模式下对其进行测试,它不会像应该的那样用记录更新本地数据库。正常工作,直到添加/更新命令为止。 有问题的代码

con = new SqlConnection(connectionstring);
con.Open();
SqlCommand command = new SqlCommand("SELECT date_last_changed_group FROM groupChanges WHERE memberid = " + memberid.ToString() + ";", con);
SqlDataReader reader = command.ExecuteReader();
bool userexists = reader.HasRows;
reader.Close();
if (userexists) {
    Console.WriteLine("User already exists in database - updating");
    SqlCommand updatecommand = new SqlCommand();
    updatecommand.Connection = con;
    updatecommand.CommandType = CommandType.Text;
    updatecommand.CommandText = "UPDATE groupChanges SET date_last_changed_group = @date WHERE memberid = @id";
    updatecommand.Parameters.AddWithValue("@id", (BigInteger)memberid);
    updatecommand.Parameters.AddWithValue("@date", DateTime.Now);
    try {
        updatecommand.ExecuteNonQuery();
    }
    catch {
        Console.WriteLine("Something went wrong");
    }
}
else {
    Console.WriteLine("User doesnt exist in database - creating new field");
    SqlCommand addcommand = new SqlCommand();
    addcommand.Connection = con;
    addcommand.CommandType = CommandType.Text;
    addcommand.CommandText = "INSERT INTO groupChanges (memberid, date_last_changed_group) VALUES (@id, @date)";
    addcommand.Parameters.AddWithValue("@id", (BigInteger)memberid);
    addcommand.Parameters.AddWithValue("@date", DateTime.Now);
    try {
        addcommand.ExecuteNonQuery();
    }
    catch {
        Console.WriteLine("Something went wrong");
    }
}
con.Close();