public void InsertRow(string connectionString)
{
    string queryString = 
        "INSERT INTO Dept (DeptNo, Dname, Loc) values (50, 'TECHNOLOGY', 'DENVER')";
    using (OracleConnection connection = new OracleConnection(connectionString))
    {
        OracleCommand command = new OracleCommand(queryString);
        command.Connection = connection;
        try
        {
            connection.Open();
            command.ExecuteNonQuery();
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
    }
}