Home > Articles > Data > Oracle

Sales Tracking Application Web Site -- Buy a Car

Oracle expert Dan Hotka shares info from Chapters 9 and 10 of his new book, Oracle8i from Scratch, which covers the entire Oracle8i database from a project point of view, building a Web site using both PL/SQL and Java. This article illustrates parts of Chapter 9 that discuss the Web site built in the book, and contains parts of the PL/SQL code used to create parts of the Web site.

This article is excerpted from Oracle8i from Scratch (Que, 2000, ISBN 0789723697).

This is an excerpt from the book Oracle8i from Scratch (Que, 2000, ISBN 0789723697). The Web site described in this article is developed in PL/SQL in Chapter 10 of the book and in Java in Chapter 11. This article illustrates the Web site built in the book as well as the PL/SQL code used to create the first Web page.

As cars are prepared for sale, they will be added to the ST_CARS_FOR_SALE table shown in Figure 1. This object tracks the inventory ID, the description of the car, and the location of the picture image on disk. HTML output can only pick up images from the disk, so all you need to do is store the location of the image in the database, not necessarily the whole picture. If the picture is stored in the database, the get_lob PL/SQL built-in procedure can be used to extract it to a specific location with a specific name that can then be referenced by the HTML output. An additional Oracle form could be added to maintain the ST_CARS_FOR_SALE, and of course, you would need a report or form to display or process the BUYER information when offers were made.

Figure 1

Sales tracking "cars for sale" object.

The Sales Tracking Web site dynamically displays auto information on those vehicles that have been added to the ST_CARS_FOR_SALE table object. Figure 2 shows the 1990 Camry Deluxe auto information in the ST_CARS_FOR_SALE object. The Web site then has the ability to display information stored in this table object. Figure 3 shows the Web site (built in Chapter 10 with PL/SQL and Chapter 11 with Java). Three buttons control the navigation of this Web page: Previous, Next, and Buy This Car. The Previous and Next buttons simply display information from the previous or next row in the ST_CARS_FOR_SALE object. For example, clicking the Next button displays the Camry information (see Figure 4).

Figure 5 shows the entry boxes displayed on the Web page when the Place Offer button is selected. Figure 6 shows the offer information being displayed on the Web page after the Place Offer button is selected in Figure 5. The Browse Inventory button returns the Web user to the original screen (refer to Figure 3). Figure 7 shows the data stored in ST_CARS_FOR_SALE after the Place Offer button is selected. The information from the Web page has been written into the database.

NOTE

This is just a sample application. A real application that takes offers over the Web would collect as many as possible, storing them in yet another table object. The author is interested in showing functionality in these examples.

Figure 2

ST_CARS_FOR_SALE data.

Figure 3

Sales Tracking Web site inventory screen.

Figure 4

Sales Tracking Web site inventory screen, next row.

Figure 5

Making an offer.

Figure 6

Offer recorded.

Figure 7

Offer data recorded.

Displaying Pictures with PL/SQL and HTML

It's easy to create simple PL/SQL procedures that display common details such as banner information and default items on a Web page. This gives the Web page a consistent look and allows for PL/SQL to be coded once and reused many times.

Listing 1 shows the code to create the banner Web page information shown in Figure 8. Notice the htp.tableOpen and the htp.tableRowOpen in lines 9 and 10. Within the "table row," notice that there are two references to htp.tableData, lines 14 and 22. Each of these tableData references makes a column in the HTML table. This gives the HTML output the ability to display text and images in a very specific and consistent position. The first column gets the metro_motors.jpg image file, lines 14 through 21. The htf.img function returns the location of the picture (in this case, the Metro Motors JPG file) stored in the virtual location ows-img. The htf.img function generates an <IMG> tag that tells HTML where an image is stored in the virtual path. The second column receives the text Metro Motors Web Site, as shown in lines 22 through 25.

Listing 1. HelloWorld PL/SQL Procedure Displaying a Banner (helloworld2.sql)

1: CREATE OR REPLACE PROCEDURE helloworld
2: AS
3: BEGIN
4:     htp.htmlopen;
5:     htp.bodyOpen;
6:     -- -------------------------------------------------
7:     -- start of our heading / banner
8:     -- -------------------------------------------------
9:     htp.tableOpen;
10:    htp.tableRowOpen
11:    (
12:        cvalign => 'CENTER'
13:    );
14:    htp.tableData
15:    (
16:        cvalue      => htf.img
17:                        (
18:                        curl        => '/ows-img/metro_motors.jpg'
19:                    ,   cattributes => 'WIDTH=100'
20:                        )
21:    );
22:    htp.tableData
23:    (
24:        cvalue  => htf.big('Metro Motors Web Site')
25:    );
26:    htp.tableRowClose;
27:    htp.tableClose;
28:    -- -------------------------------------------------
29:    -- End of our heading / banner
30:    -- -------------------------------------------------
31:    htp.p('HelloWorld');
32:    htp.bodyClose;
33:    htp.htmlClose;
34: END;
35: /

Figure 8

Metro Motors Web site banner page.

NOTE

If your browser doesn't show the graphic, check your OAS virtual mappings to make sure that the JPG image file is in the directory for which the virtual directory is configured.

At this point, it's easy to create a procedure called display_banner and simply call it whenever you create a new Web page, allowing the banner information to be coded once and used throughout the Web application. If you need to change the banner information, you simply change one procedure, and the change would then be reflected automatically throughout the application on its next Web browser access. Notice that the display_banner procedure in Listing 2 is very similar to the code in Listing 1—lines 7–25 in Listing 2 are very similar to lines 9–27 in Listing 1. The only real difference is at lines 3 and 22 in Listing 2; the p_caption variable replaces the hard-coded Metro Motors banner text, so that this procedure can be used for any banner by simply putting ?p_caption=<some text> on the URL line.

Listing 2. DISPLAY_BANNER PL/SQL Procedure (display_banner.sql)

1: CREATE OR REPLACE PROCEDURE display_banner
2: (
3:     p_caption   IN VARCHAR2 DEFAULT 'Metro Motors Web Site'
4: )
5: AS
6: BEGIN
7:     htp.tableOpen;
8:     htp.tableRowOpen
9:     (
10:        cvalign => 'CENTER'
11:    );
12:    htp.tableData
13:    (
14:        cvalue      => htf.img
15:                        (
16:                        curl        => '/ows-img/metro_motors.jpg'
17:                     ,   cattributes => 'WIDTH=100'
18:                        )
19:    );
20:    htp.tableData
21:    (
22:        cvalue  => htf.big(p_caption)
23:    );
24:    htp.tableRowClose;
25:    htp.tableClose;
26: END;
27: /

Listing 3 (helloworld3) shows how to change the helloworld procedure to call the display_banner procedure:

Listing 3. HelloWorld PL/SQL Procedure Using Procedure display_banner (helloworld3.sql)

CREATE OR REPLACE PROCEDURE helloworld
AS
BEGIN
    htp.htmlopen;
    htp.bodyOpen;
    -- -------------------------------------------------
    -- start of our heading / banner
    -- -------------------------------------------------
    display_banner
    (
        p_caption => 'Metro Motors Web Site'
    );
    -- -------------------------------------------------
    -- End of our heading / banner
    -- -------------------------------------------------
    htp.p('HelloWorld');
    htp.bodyClose;
    htp.htmlClose;
END;
/

The display_banner procedure not only creates the same HTML output, but you can use it in related Web pages to give the identical visual attributes without having to add the code to each additional Web page.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020