tailieunhanh - Hướng dẫn sử dụng MySQL part 9

Chúng tôi đã dành toàn bộ cuốn sách cho đến nay thảo luận về cơ sở dữ liệu như thể nó tồn tại trong một số loại chân không. Nó phục vụ mục đích của nó chỉ khi được sử dụng bởi ứng dụng khác. Do đó chúng tôi cần xem xét như thế nào cơ sở dữ liệu liên quan đến các yếu tố khác của một ứng dụng cơ sở dữ liệu trước khi khám phá các chi tiết của phát triển ứng dụng cơ sở dữ liệu bằng các ngôn ngữ khác nhau. | DRAFT 8 24 01 Database Applications We have spent the entire book so far discussing the database as if it exists in some sort of vacuum. It serves its purpose only when being used by other applications. We should therefore take a look at how the database relates to the other elements of a database application before exploring the details of database application development in various languages. This detour examines conceptual issues important not only to programming with MySQL but also to programming with any relational database engine. Our look at database programming covers such complex issues as understanding the basic architectures common to Web-oriented database applications and how to map complex programming models into a relational database. Architecture Architecture describes how the different components of a complex application relate to one another. A simple Web application using Perl to generate dynamic content has the architecture shown in Figure 9-1. This architecture describes four components the Web browser the Web server the Perl CGI engine and the MySQL database. Figure 9-1. . The architecture of a simple Web application Architecture is the starting point for the design of any application. It helps you identify at a high level all of the relevant technologies and what standards those technologies will use to integrate. The architecture in Figure 9-1 for example shows the Web browser talking to the server using HTTP. Copyright 2001 O Reilly Associates Inc. 158 DRAFT 8 24 01 As we will cover in the later chapters of this section MySQL exposes itself through a variety of APIs tailored to specific programming languages. Java applications access MySQL through JDBC Python applications through the Python DB-API etc. The architecture above clearly shows to any observer that the application in question will use the Perl DBI API to access MySQL. There are numerous architectures used in database applications. In this chapter we will cover the .