PHP 5/MySQL Programming- P82 pptx

T his book begins by looking at HTML pages, which are essentially static documents. It then reveals how to generate dynamic pages with the powerful PHP language. The last few chapters show how to use a database management system such as MySQL to build powerful data structures. This chapter ties together the PHP programming and data programming aspects to build a full-blown data-management system for the spy database. The system you learn can easily be expanded to any kind of data project you can think of, including e-commerce applications. Specifically, you learn how to: • Design a moderate-to-large data application • Build a library of reusable data functions • Optimize functions for use across data sets • Include library files in your programs There isn’t really much new PHP or MySQL code to learn in this chapter. The focus is on building a larger project with minimum effort. B u i l d i n g a T h r e e -T i e r e d D a t a A p p l i c a t i o n 12 CHAPTER 384 P H P 5 /M y S Q L P r o g r a m m i n g f o r t h e A b s o l u t e B e g i n n e r Introducing the SpyMaster Program The SpyMaster program is a suite of PHP programs that allows access to the spy database created in chapter 11, “Data Normalization.” While the database cre- ated in that chapter is flexible and powerful, it is not easy to use unless you know SQL. Even if your users do understand SQL, you don’t want them to have direct control of a database, because too many things can go wrong. You need to build some sort of front-end application to the database. In essence, this system has three levels. • The client computer handles communication with the user. • The database server (MySQL) manages the data. • The PHP program acts as interpreter between the client and database. PHP provides the bridge between the client’s HTML language and the database’s SQL language. This kind of arrangement is frequently called a three-tier architecture . As you examine the SpyMaster program throughout this chapter, you learn some of the advantages of this particular approach. Viewing the Main Screen Start by looking at the program from the user’s point of view as shown in Figure 12.1. The main page has two sections. The first is a series of data requests. Each of these requests maps to a query. Viewing the Results of a Query When the user selects a query and presses the Submit button, a screen like the one in Figure 12.2 appears. The queries are all prebuilt, which means the user cannot make a mistake by typing in inappropriate SQL code. It also limits the usefulness of the database. Fortunately, you can add new queries. 385 C h a p t e r 1 2B u i l d i n g a T h r e e -T i e r e d D a t a A p p l i c a t i o n FIGURE 12.1 The entry point to the SpyMaster database is clean and simple. FIGURE 12.2 The results of the query are viewed in an HTML table. Viewing Table Data The other part of the main screen (shown again in Figure 12.3) allows the user to directly manipulate data in the tables. Since this is a more powerful (and thus dan- gerous) enterprise, access to this part of the system is controlled by a password. As an example, by selecting the agent table I see a screen like Figure 12.4. 386 P H P 5 /M y S Q L P r o g r a m m i n g f o r t h e A b s o l u t e B e g i n n e r FIGURE 12.3 From the main screen you can also access the table data with a password. FIGURE 12.4 The editTable screen displays all the information in a table. 387 C h a p t e r 1 2B u i l d i n g a T h r e e -T i e r e d D a t a A p p l i c a t i o n From this screen, the user can see all the data in the chosen table. The page also gives the user links to add, edit, or delete records from the table. Editing a Record If the user chooses to edit a record, a screen similar to Figure 12.5 appears. The Edit Record page has some important features. First, the user cannot directly change the primary key. If she could do so, it would have profound destabilizing consequences on the database. Also note the way the operationID field is pre- sented. The field itself is a primary key with an integer value, but it would be very difficult for a user to directly manipulate the integer values. Instead, the pro- gram provides a drop-down list of operations. When the user chooses from this list, the appropriate numerical index is sent to the next page. Confirming the Record Update When the user clicks the button, a new screen appears and announces the suc- cessful update as in Figure 12.6. Deleting a Record The user can also choose to delete a record from the Edit Table page. This action results in the basic screen shown in Figure 12.7. FIGURE 12.5 The user is editing a record in the agent table. . with the powerful PHP language. The last few chapters show how to use a database management system such as MySQL to build powerful data structures. This chapter ties together the PHP programming. user. • The database server (MySQL) manages the data. • The PHP program acts as interpreter between the client and database. PHP provides the bridge between the client’s HTML language and. effort. B u i l d i n g a T h r e e -T i e r e d D a t a A p p l i c a t i o n 12 CHAPTER 384 P H P 5 /M y S Q L P r o g r a m m i n g f o r t h e A b s o l u t e B e g i n n e r Introducing the SpyMaster Program The SpyMaster program is a suite of PHP programs that allows access to the spy database created in chapter 11, “Data Normalization.”