在Delphi中实现数据库的访问部件的设计

由于Delphi开发的易用性和快速性,很多原来使用Foxpro 和visual Foxpro编程的程序员转向了Delphi,但是原来的应用系统尤其是应用数据,不可能一下丢弃,因而需要用Delphi来维护xBase数据库的应用系统.Delphi中现有的数据访问部件可以连接目前绝大部分的数据库,但用在连接Foxpro系列的数据库时,只能对记录进行逻辑删除,不能进行物理删除,而且数据访问部件也没有提供在Foxpro中显示软删除(set delete on/off)、得到当前记录号(RecNo)、是否精确匹配(set Exact on/of)等功能.而要实现以上功能,只能通过调用BDE函数来实现;调用BDE函数,参数多而繁,使Delphi操作DBF数据表带来很多不便,编程效率低,并且容易出错.为了解决这些问题,本文用Borland 公司开发的 Delphi5.0平台顺利地完成了对Ttable控制的继承,进行了使其具有相当于Foxpro下易用的一些功能.

The Design of the Database Access Component in the Delphi

Many programmers who ever used Foxpro and Visual Foxpro now turn to Delphi, because of it user-friendliness. Primary application system especially application data can't be abandoned immediately, so Delphi is needed to maintain the application system of xBase database. The data access component of Delphi can link most databases, but when it links the database of Foxpro and when data record is to be deleted?record can only be deleted logically but not deleted physicall. And the data Access component of Delphi doesn't have the function of set delete on/off, RecNo, set Exact on/off, etc. In order to realize these functions, BDE function must be used. BDE function has many parameters. In view of this situation, in order to solve problems, the article has adopted Delphi5.0 platform which was exploited by Borland Company and finished the inheritance of Ttable's controlling.