C# SQLParameters

Always use parameters. This allows one to safely inject the right data. 

public int AddUser(Logic.Employee details)
{
    int lastId = 0;
    string MyConString = "server=localhost;database=crawler_attendance;Username=root;Password=crawl;";
    MySqlConnection conn = new MySqlConnection(MyConString);

    try
    {
    string dbQuery = string.Empty;
    dbQuery = String.Format(@"INSERT INTO employeeTEST(username,firstname,lastname,company)
                  VALUES(@username,@firstname,@lastname,@company)");

    MySqlCommand cmd = new MySqlCommand(dbQuery, conn);
    cmd.Parameters.AddWithValue("@username", details.userName);
    cmd.Parameters.AddWithValue("@firstname", details.firstName);
    cmd.Parameters.AddWithValue("@lastname", details.lastName);
    cmd.Parameters.AddWithValue("@company", details.company);
    conn.Open();
    cmd.ExecuteNonQuery();

    cmd.Parameters.Add(new MySqlParameter("lastId", cmd.LastInsertedId));
    lastId = Convert.ToInt32(cmd.Parameters["@lastId"].Value);
    }
    catch (Exception e)
    {
    conn.Close();
    }
    finally
    {
    conn.Close();
    }

    return lastId;
}