数据库应用程序的开发（外文文献翻译）.doc

Designing database applications Database applications let users interact with information that is stored in databases. Databases provide structure for the information, and allow it to be shared among different applications. Delphi provides support for relational database applications. Relational databases organize information into tables, which contain rows (records) and columns (fields). These tables can be manipulated by simple operations known as the relational calculus. When designing a database application, you must understand how the data is structured. Based on that structure, you can then design a user interface to display data to the user and allow the user to enter new information or modify existing data. The following topics introduce common considerations when designing a database application: Using databases Database architecture Designing the user interface Using databases Delphi includes many components for accessing databases and representing the information they contain. They are grouped according to the data access mechanism: The BDE page of the Component palette contains components that use the Borland Database Engine (BDE). The BDE defines a large API for interacting with databases. Of all the data access mechanisms, the BDE supports the broadest range of functions and comes with the most supporting utilities. It is the best way to work with data in Paradox or Dbase tables. However, it is also the most complicated mechanism to deploy. For more information about using the BDE components, see Using the Borland Database Engine. The ADO page of the Component palette contains components that use ActiveX Data Objects (ADO) to access database information through OLEDB. ADO is a Microsoft Standard. There is a broad range of ADO drivers available for connecting to different database servers. Using ADO-based components lets you integrate your application into an ADO-based environment (for example, making use of ADO-based application servers). For more i