Section 18.0. Introduction
18.0. IntroductionWhen you store information in your database, you can easily retrieve it for use on the Web in a variety of ways. Query results can be displayed as unstructured paragraphs or as structured elements such as lists or tables; you can display static text or create hyperlinks. Query metadata can be useful when formatting query results, too, such as when generating an HTML table that displays a result set and uses its metadata to get the column headings for the table. These tasks combine statement processing with web scripting, and are primarily a matter of properly encoding any special characters in the results (like & or <) and adding the appropriate HTML tags for the types of elements you want to produce. This chapter shows how to generate several types of web output from query results:
The chapter also covers techniques for inserting binary data into your database and for retrieving and transferring that kind of information to clients. (It's easiest and most common to work with text for creating web pages from database content, but you can also use MySQL to help service requests for binary data such as images, sounds, or PDF files.) You can also serve query results for download rather than for display in a page. Finally, the chapter discusses the use of template packages for generating web pages. The recipes here build on the techniques shown in Chapter 17 for generating web pages from scripts and for encoding output for display. See that chapter if you need background in these topics. Scripts to create the tables used in this chapter are located in the tables directory of the recipes distribution. The scripts for the examples can be found under the directories named for the servers used to run them. For Perl, Ruby, PHP, and Python examples, look under the apache directory. Utility routines used by the example scripts are found in files located in the lib directory. (See Section 17.2 for information on configuring Apache so that scripts can be run by it and find their library files.) For Java (JSP) examples, look under the tomcat directory; you should already have installed these in the process of setting up the mcb application context (Section 17.3). Note that although the scripts in this chapter are intended to be invoked from your browser after they have been installed, many of them (JSP pages excepted) can also be invoked from the command line if you want to see the raw HTML they produce (Section 17.2). Not all languages are represented in every section of this chapter. If a particular section has no example for a language in which you're interested, check the recipes distribution. It might contain the implementation you want, even if it's not shown here. |
