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Nội dung Text: MASTERING SQL SERVER 2000- P18

  1. 870 CHAPTER 23 • THE WEB ASSISTANT WIZARD option seen in Figure 23.11 will instruct the Web Assistant Wizard to help format the Web page. The only real problem with using the Wizard to format the Web page is that it turns out kind of bland, a white background with black text. If you want something a little snazzier than that, you can select the option to use a predefined template. To create this template, you will need to know how to program in HTML code and have created the template beforehand. Once you have a template, you need to only point the Web Assistant Wizard to the right file by selecting the second option. Because HTML coding is out of the scope of this book, you are going to have the Web Assis- tant Wizard format the Web page for you by selecting the first option on the screen. FIGURE 23.11 The Web Assistant Wizard can help you format the Web page. Specifying Titles If you instructed the Web Assistant Wizard to use a template file, you would skip ahead a few pages to limiting the number of rows returned, but because you decided to ask for help, you need to tell the Wizard how you want your page to look. The first question, as seen in Figure 23.12, asks what title you want on your Web page; this will show up in the title bar at the top of the Web browser. The next question asks what title you want to give the table that is used to display the data on the Web page; this shows up just above the table at the top of the page. The final question
  2. PUBLISHING DATA WITH THE WEB ASSISTANT WIZARD 871 asks what size the title should be just above the table; the default is H3 (heading 3), and the size shown is actual. The checkbox at the bottom of the page will allow you to place a time- and datestamp at the bottom of the Web page so that you will know the last time it was updated. This is especially helpful if you have instructed the Wiz- ard to automatically update your Web page. For the purpose of demonstration, you will change the title of the Web page to Northwind Employees and the title of the table to Employee Listing, then click Next. FIGURE 23.12 The Wizard needs some information to help you format your Web page. PA R T V Development with SQL Server Formatting the Table The data from the tables in your database is displayed on the Web page as a table—a table that needs to be formatted. Therefore, the next screen will allow you to change the way the table looks on the Web page. The first choice you see at the top of the screen (as shown in Figure 23.13) asks whether the column names should be displayed at the top of the table. All columns have a name that is assigned when the table is designed; if you want that name to be displayed in the table on the Web page, select the Yes, Display Column Names option. If you do not want these to be displayed, select the No, Display Data Only option.
  3. 872 CHAPTER 23 • THE WEB ASSISTANT WIZARD The next choice to make on this screen is the style of font that you want to use to display the data in the table. The four choices are listed with an example of what the text will look like in the table. At the bottom of the screen, there is a checkbox that will turn on or off the border lines around the table. If border lines are on, the data in each cell of the table will have a box around it; if border lines are off, there will be no box around the data cells. FIGURE 23.13 The table that is dis- played on the page can be formatted to suit your needs. For this example, you will choose to display column names, leave the font as fixed, and leave the border-lines option checked, and then click Next. Linking to Other Sites Usually, when you open a Web page, you see text that is a different color and under- lined. When you move your mouse over this special text, the cursor changes, and when you click the text, you are transported to a different Web page. This special text is called a hyperlink, and on the screen that you see in Figure 23.14, you can add hyperlinks to your page. If you select the first option on the page—No—you will not add any links to your page. If you want to add a single link to the bottom of your page, enter the address of the page and a label for the page by selecting the Yes, Add One Hyperlink option and filling in the data. For example, if you want to add a hyperlink to your company’s main Web page (called the home page), you could enter
  4. PUBLISHING DATA WITH THE WEB ASSISTANT WIZARD 873 as the link and MyCompany Home Page as the label. Doing so would create a link at the bottom of the Web page labeled MyCompany Home Page that would take users to Just below that, there is a text box that will allow you to enter a Transact-SQL SELECT query to pull hyperlink information out of a SQL Server table. The table needs to be created and populated in advance, but this option can come in very handy if you have a large number of links to add to the page or if your links are always changing. FIGURE 23.14 Adding hyperlinks to your page can make other company sites easier to find. PA R T V Development with SQL Server If you’re following along, please select the option to add a single link, and enter in the Hyperlink URL textbox and Sybex Books in the Hyperlink Label textbox, then click Next. Limiting the Rows Displayed Even if you entered a WHERE clause (as seen in Figure 23.7 earlier in this chapter), you may still get too many rows. For instance, if you work for a large company and decide to display the records where the last name is Smith, you may see a large num- ber of records. On the screen shown in Figure 23.15, you can limit the number of rows displayed by SQL Server.
  5. 874 CHAPTER 23 • THE WEB ASSISTANT WIZARD The first option does just as it reads by displaying all the rows in the result set. If you want to limit the number of rows, you should select the second option, labeled Yes, and then enter the number of records to be displayed on the Web page. Depending on the number of rows being displayed, you may want to split the data across several Web pages, because readers do not want to have to scroll through a large number of records at once (and larger pages take longer to download). To split the data across several pages, simply select the option at the bottom of the page that states Yes, Link the Successive Pages Together and then enter the number of records to be displayed on each page in the Limit Each Page to x Rows of Data textbox. FIGURE 23.15 You may not need to display all rows of data, but if you do, you may want to split them across multiple Web pages. In this example, you are going to leave the default of displaying all rows on a sin- gle page and click Next. The Final Page On the final screen of the Web Assistant Wizard, you will see a list of all the choices that you have made throughout the course of this Wizard; read through each choice and make sure it agrees with you. At the bottom of that laundry list, there is a button (as seen in Figure 23.16) labeled Write Transact-SQL to File, which will take all of your hard work, transform it into Transact-SQL code, and store it in a text file on your hard disk. This file can then be opened in Query Analyzer (a tool for running Transact-SQL code) and executed to re-create your Web Assistant Wizard job if the job gets damaged
  6. PUBLISHING DATA WITH THE WEB ASSISTANT WIZARD 875 or deleted for some reason. This makes recovery much easier and therefore is highly recommended. FIGURE 23.16 On the last screen, you are given the option to review and save your changes. PA R T V Development with For this example, click the Write Transact-SQL to File button and save the text as SQL Server nwind_emp.sql. When that is done, click Finish to create the Web page. The Steps to Create the Northwind Employees Web Page As promised, here are all of the steps used to create the Northwind Employees Web page (just in case you wanted to wait until the end): 1. Open Enterprise Manager by selecting it from the SQL Server 2000 group under Programs on the Start menu. 2. From the Tools menu, select Wizards. 3. Expand Management and double-click the Web Assistant Wizard. 4. On the welcome screen, click Next. 5. Select Northwind as the database from which to publish. 6. Name the job Northwind Employees and select Data from the Tables and Columns That I Select. 7. Select Employees as the table from the drop-down list and click the Add All but- ton to publish data from all columns, then click Next.
  7. 876 CHAPTER 23 • THE WEB ASSISTANT WIZARD 8. Select the All of the Rows option to publish all rows of data and click Next. 9. Select the At Regularly Scheduled Intervals choice and click Next. 10. Change the schedule for the job to every 2 minutes and click Next. 11. Select the default directory to place the Web page in and click Next. 12. Select the Yes, Help Me Format the Web Page option and click Next. 13. On the next page, change the title of the Web page to Northwind Employees, change the title of the table to Employee Listing, and click Next, leaving the rest of the choices as the default settings. 14. On the next page, instruct the Web Assistant Wizard to display the column names and use a fixed font, then click Next. 15. On the next page, add a single hyperlink to labeled Sybex Books and click Next. 16. On the next screen, you will instruct SQL Server to display all of the rows from the result set and leave them on the same page, then click Next. 17. On the final screen, you will save all of the code to a text file by clicking the Write Transact-SQL to File button, then entering nwind_emp.sql as the file- name and clicking Save. 18. Finally, click Finish to create the Web Assistant Wizard job and Web page. Now you are ready to verify that everything was done correctly and view your Web page. Viewing the Page If you have followed along though this chapter, you should have a Web publishing job ready to go at this point. To verify this, you can do the following: 1. In Enterprise Manager (which should still be open), expand your server, then Management. 2. Under Management, select Web Publishing. 3. In the contents pane (on the right), double-click the Northwind Employees job. 4. On the Properties page, read the code to see exactly what SELECT statement is used to generate the result set being displayed on your Web page.
  8. PUBLISHING DATA WITH THE WEB ASSISTANT WIZARD 877 PA R T V Development with Not only do you have an entry in the Web Publishing section of Management, you have a new job scheduled. Let’s view the job that the Web Assistant Wizard created for you: SQL Server 1. In Enterprise Manager, expand the SQLServerAgent under Management and select Jobs (if you are a master job server, as discussed in Chapter 17, you need to select Local Jobs under Jobs). 2. In the contents pane, double-click the job named Northwind Employees. 3. Select the Steps tab and double-click step number 1 to view the code that creates the Web page. Notice that this is a special system stored procedure named sp_runwebtask.
  9. 878 CHAPTER 23 • THE WEB ASSISTANT WIZARD 4. Click Cancel and select the Schedules tab. 5. Double-click the schedule to see when the job will activate. 6. Click Cancel, then click Cancel again to return to Enterprise Manager. TI P If you want to change how often the Web page is created, you may do so from the Schedules tab of the job that creates the Web page. If you want to stop updating the Web page, you can disable the job altogether by unchecking the Enabled checkbox on the Gen- eral tab of the job’s properties.
  10. PUBLISHING DATA WITH THE WEB ASSISTANT WIZARD 879 You probably want to see the fruits of your labors by viewing the Web page itself. Let’s do that now by opening it right from the directory it is stored in on your hard disk: 1. Click the Start button and select Run. 2. In the Open text box, type C:\Program Files\Microsoft SQL Server\ 80\Tools\HTML\WebPage1.htm (if you have installed SQL Server to a dif- ferent drive, please replace the C with your drive letter). 3. This will open your Web browser and display the Web page. Notice the title bar at the top, the table title just above the table, the boxes around the data (the table border), and, at the bottom, the link to Sybex Books. PA R T V Development with SQL Server 4. At the top of the Web page, you will see a timestamp; wait for 2 minutes and click the Refresh button on your browser—the timestamp should be updated, indicating that the job is running every 2 minutes just as instructed. 5. Close your Web browser. Armed with this knowledge, you are now able to publish your data on the Web quickly and easily.
  11. 880 CHAPTER 23 • THE WEB ASSISTANT WIZARD Summary The Web Assistant Wizard is a simple Wizard, but is very useful, which is why we ded- icated an entire chapter to its use. The first topic we discussed was why you would even want your data on the Web. We gave some scenarios of a store catalog, a phone list, and event schedules on the Web. All of these scenarios definitely benefit from being on the Web, and there are many, many more scenarios that you will be able to add to that list. After discussing the need to put your data on the Web, we went through each and every screen in the Web Assistant Wizard and discussed each one in detail, describing each choice and when each option would be most helpful. The Web Assistant Wizard, useful as it is, is somewhat limited when you look at all that you can do with SQL Server on the Web. In the next chapter, we will look into some more powerful methods of putting your data on the Web by integrating SQL Server 2000 with Internet Information Server.
  12. CHAPTER 24 Integrating SQL Server with Internet Information Server F E AT U R I N G : What Is Internet Information Server? 882 Active Server Pages 884 Remote Data Service 900 Returning Results as XML 910 Querying SQL Server through HTTP 912 Summary 919
  13. I n the last chapter, you saw that the Web Assistant Wizard makes it easy to gen- erate HTML pages from data stored in a SQL Server database. However, the con- nections between SQL Server and the Internet go much deeper than just generating HTML pages. In this chapter, we’ll explore some of the ways in which you can use SQL Server together with Microsoft’s Web server offering, Internet Information Server. You’ll learn about using ADO in Web pages, Remote Data Ser- vices, HTTP queries, and SQL Server’s new XML features. Some of these features depend on Microsoft Internet Information Server, and some do not, but they all require you to be running a Web server of one variety or another. We’ll concentrate on IIS because it’s closely integrated with Windows and should be available to most SQL Server installations. What Is Internet Information Server? Internet Information Server (IIS) is a Web server application. In particular, it’s the Web server application designed by Microsoft for high-volume use on Windows NT plat- forms. A Web server is a program that responds to requests from Internet or intranet clients (typically Web browsers) by sending back files. These files might be HTML pages or other documents. When you type a URL into a Web browser, such as, you’re telling your browser to send a Hypertext Transfer Protocol request to that address (that’s where the http prefix comes from). The server at that address (presumably IIS, in the case of looks at the request, decides which file it refers to, and sends the file back to the user. Originally, Web servers such as IIS could return only static pages containing infor- mation placed there for users. However, over time the job of Web servers has expanded to include dynamic content. In particular, IIS offers several ways to merge data from SQL Server with a Web page. In this chapter, we’ll cover three of those options: • ADO code in Active Server Pages • Remote Data Services • XML data Installing IIS There are two versions of IIS that you’re likely to run across as you’re working with SQL Server 2000: IIS 4 and IIS 5.
  14. WHAT IS INTERNET INFORMATION SERVER? 883 IIS 4 is an optional program for Windows NT 4. It’s not included as a part of the Windows NT operating system. To install IIS 4, you need to install the Windows NT Option Pack. The Option Pack is available as part of MSDN or TechNet subscrip- tions, or you may download it from downloads.asp. Some other products, such as Microsoft Visual Studio, also ship with copies of the Option Pack. With Windows 2000, Microsoft has made IIS part of the core operating system. If you install Windows 2000 Server or Advanced Server, you get the chance to include IIS 5 as part of the installation. Although the interface for managing IIS differs slightly between IIS 4 and IIS 5, either version will work perfectly well with SQL Server 2000. You can use the tech- niques in this chapter with both versions of IIS. NOTE For details on managing and setting up IIS, refer to the Windows NT Option Pack PA R T or Windows 2000 documentation. V A Few Words about Security Development with There’s something about a Web server that’s irresistibly attractive to crackers, script SQL Server kiddies, and other Internet lowlifes. Over the past few years, unfortunately, there have been a number of fairly high-profile security holes found in Internet Information Server. Some of these have allowed outsiders to cause your server to crash just by sending particular HTTP requests to it. Others have exposed sensitive data, bypassing SQL Server and IIS security entirely. If you’re going to hook up your SQL Server via IIS to the public Internet, you must be concerned with security, unless all of your data should be open to everyone in the world. We’d like to offer complete instructions for securing your server to prevent intru- sions and data loss. However, this is a quickly changing area, and any advice we could give would be out of date by the time you read it. Rather than provide you with a false sense of security, we’ll suggest a few resources that you should use to keep up with the ins and outs of Web security. Your first line of defense is the Microsoft Security Advisor Web site at http://www Microsoft has been diligent about publiciz- ing security problems and providing patches to eliminate such problems. Consider visiting this Web site on a weekly basis to check for new problems that affect your installation. You should also check out their Product Security Notification Service, which will send you e-mail when new problems are discovered.
  15. 884 CHAPTER 24 • INTEGRATING SQL SERVER WITH INTERNET INFORMATION SERVER If you’re running IIS 4, you should refer to the IIS 4 security checklist at http://www This page covers all the steps neces- sary to make an IIS 4 installation as secure as possible, with links to relevant articles and recommendations. If you’re running IIS 5, you should download the Windows 2000 Internet Server Security Configuration Tool from .asp?ReleaseID=19889. This tool, released in March 2000, will help you develop and apply a security policy for Windows 2000–based Web servers. Finally, if you get seriously interested in this topic, or if you’re responsible for very sensitive data, we recommend subscribing to the NTBugTraq mailing list. This is a moderated mailing list that’s independent of Microsoft, on which many developers and system administrators discuss all aspects of Windows NT security. You can get signed up or read the list archives at Active Server Pages The simplest way to display data from SQL Server on a Web page is to use an Active Server Page that makes use of ADO. In this section, we’ll review the general design of Active Server Pages (ASP pages) and then see how you can use them in conjunction with SQL Server and IIS to display SQL Server data in a Web page. NOTE Because ASP stands for Active Server Pages, it would make sense to speak of AS pages as shorthand. However, perhaps by analogy with HTML pages, nearly all developers refer to ASP pages. So don’t blame us if this doesn’t make any sense. What Are Active Server Pages? To understand Active Server Pages, let’s start with regular HTML (Hypertext Markup Language) pages. Here’s what a very simple HTML page looks like when opened in a text editor on the server: HTML Example
  16. ACTIVE SERVER PAGES 885 This is a simple HTML page. As you can see, there are two types of information intermingled in the source file for an HTML page. First, there is actual content to be displayed to the user, such as “This is a simple HTML page.” Second, there is markup information that tells the browser how to display the content. For example, the text between and defines the title of the page. and are examples of HTML tags, instructions for display of content. Note that each tag is matched by a corre- sponding tag beginning with a / character to indicate the end of a particular process- ing directive. Table 24.1 lists some common HTML tags. NOTE We won’t try to teach you all the ins and outs of HTML in this book. Instead, PA R T we’ll show simple examples that make use of only a few HTML tags. For an in-depth tutor- ial on HTML, see Mastering HTML 4.0 (by Deborah S. Ray and Eric J. Ray, Sybex Inc. 1997). V Development with TABLE 24.1: COMMON HTML TAGS Tags Meaning SQL Server Comment and Bold and Body of page Line break and Data input form and Header information and HTML page and Heading, size 1 and Italics Data input control and Paragraph and Table and Table cell
  17. 886 CHAPTER 24 • INTEGRATING SQL SERVER WITH INTERNET INFORMATION SERVER TABLE 24.1: COMMON HTML TAGS (CONTINUED) Tags Meaning and Table row and Page title and Underline Suppose this file is saved on your Web server under the name HTMLExample.htm. In this case, when a user browses to HTMLExample.htm, these steps take place: 1. The user’s browser sends a Hypertext Transfer Protocol (HTTP) request to the Web server for the particular page. 2. Internet Information Server locates the file and sends its contents back to the browser. 3. The browser interprets the HTML tags and displays the resulting text on-screen. Figure 24.1 shows the end result of this sequence. Note that the address bar in the browser contains the HTTP request that was used to locate the page. FIGURE 24.1 HTML page in the browser When working with HTML pages, IIS functions as a sort of file clerk. Its job is just to look at the incoming HTTP request, locate the appropriate file, and send the file back to the browser. HTML pages are static Web pages whose content is always the same (at least until the developer edits the page). Active Server Pages, by contrast, are dynamic Web pages. The file that’s stored on the server is not precisely the file that is sent out to the browser. Instead, the file on
  18. ACTIVE SERVER PAGES 887 the server contains additional instructions that are executed on the server, with the results being sent to the browser. For example, here’s a simple ASP file: ASP Example This is a simple ASP page. V As with the HTML file, the ASP file includes both content (“This is a simple ASP Development with page.”) and tags (). It also contains a third type of information: code to be executed on the server. Everything between the tokens is executed by IIS SQL Server before the file is sent to the browser. You can see that there’s a small program embed- ded in this file between sets of those tokens. It starts by telling IIS that the program- ming language is VBScript. It then declares a variable i and uses it in a For…Next loop. The body of the loop uses the Write method of the Response object (an object supplied by IIS) to output text to the Web page. When a user browses to this page, these steps take place: 1. The user’s browser sends a Hypertext Transfer Protocol (HTTP) request to the Web server for the particular page. 2. Internet Information Server locates the file and notes that it’s an ASP page. 3. IIS creates an HTML file by combining the static text and tags on the page with the results of the code on the page. 4. IIS sends the resulting HTML file to the browser. 5. The browser interprets the HTML tags and displays the resulting text on-screen. The result of this sequence is shown in Figure 24.2.
  19. 888 CHAPTER 24 • INTEGRATING SQL SERVER WITH INTERNET INFORMATION SERVER FIGURE 24.2 Simple ASP page in a browser To prove that the file seen by the browser is different from the original ASP file, you can use the browser’s View ➣ Source command. In this case, the HTML source looks like this: ASP Example This is a simple ASP page. 1 2 3 4 5 As you can see, all of the programming content has been removed from the page by IIS and replaced by its results. You’re not limited to VBScript in developing ASP pages. IIS supports VBScript, JScript, Perl, and REXX programming languages. For example, here’s the same ASP page rewritten using JScript (the scripting variant of the Java programming language):
  20. ACTIVE SERVER PAGES 889 ASP Example This is a simple ASP page.
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