Designing with data modules

by Mark Cashman

Data modules are a specialized type of form descended from TDataModule. Normally, you place components that descend from TDataSet and TDataSource on a data module (TTable and TQuery, for example), but data modules can contain any non-visual component.

多线程idhttp下载文件源代码

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ComCtrls, StdCtrls, IdComponent, IdTCPConnection, IdTCPClient,
IdHTTP, IdBaseComponent, IdAntiFreezeBase, IdAntiFreeze,
IdThreadComponent, IdFTP ,IdException;
type
MyException1 = class(exception)//自定义的异常类
end;

Multithreading in Database Applications

In most scenarios, database applicationsyou create with Delphi are single threaded – a query you run against the database needs to finish (processing of the query results) before you can fetch another set of data.

To speed up data processing, for example, fetching data from the database to create reports, you can add an additional thread to fetch and operate on the result (recordset).

Delphi 7 使用 JSON

JSON(JavaScript Object Notation) 是一种轻量级的数据交换格式。易于人阅读和编写，
同时也易于机器解析和生成。它基于JavaScript（Standard ECMA-262 3rd Edition - December 1999）的一个子集。 JSON采用完全独立于语言的文本格式，但是也使用了类似于C语言家族的习惯（包括C, C++, C#, Java, JavaScript, Perl, Python等）。
这些特性使JSON成为理想的数据交换语言。
Delphi7中不支持JSON文件的解析，可以下载LkJSON(一个JSON的解析文件)，然后进行解析。例如

Multi Thread Delphi Example

Illustrates how to use Absolute Database in multithreaded application.