• An application can include zero or more reports.
• A Power Objects report contains five areas in which you place objects, such as static text and text fields: ReportHeader, PageHeader, Detail, PageFooter, and ReportFooter. In general, you will add objects to the Detail area, but you may or may not have objects in the other report areas.
• You can add a group to a report by clicking the Report Section button on the Object Palette and adding it to the report.
• When you add a group to a report, two areas are also added to the report: GroupHeader and GroupFooter.

What Comes Next?

On Day 19, "An Overview of Oracle Database Security and Tuning," you will learn how to create database roles and users, granting privileges, using synonyms, determining the execution plan for a SQL statement, and other topics.

Q&A

Q Can you view the inherited code for a method in an instance of the class that has been added to a form or report?
A Unfortunately, no. You can view the method code for a class only by invoking the property sheet for the class that contains the code you want to see.
Q Can a Power Objects report be designed so that the format of a field depends on its contents?
A Yes. You can use a method, such as Validate, to inspect the field value and change another field property, such as FontBold.
Q Are there any other products included with the Oracle Power Objects 2.0 CD-ROM?
A Yes! The Oracle Power Objects 2.0 CD-ROM includes a full version of Crystal Reports Professional Version 5.0. Using your Web browser, you can order Power Objects from the Oracle Store at www.oracle.com; these products are not included on the CD-ROM accompanying this book.

Workshop

The purpose of the Workshop is to allow you to test your knowledge of the material discussed in the lesson. See if you can correctly answer the questions in the quiz and complete the exercises before you continue with tomorrow's lesson.

Quiz

1. True or false? A report's RecordSource property must reference a single table or view; it cannot join two or more tables.
2. True or false? Power Objects supports a maximum of three levels of inheritance. In other words, you can create class A, add an instance of class A on class B, and add an instance of class B on class C.
3. If you can validate user input in a Power Objects application with the Validate method, why would you need to use database constraints and triggers to enforce data integrity?

Exercises

1. Power Objects includes a number of predefined classes. If you examine the contents of the Classes folder, you'll see a class named clsMeter. Add an instance of it to MyForm. See if you can figure out how to link the meter to the X position of the mouse on the form.
2. Use Power Objects to build a report which contains a list of the instructors that belong to each department. Add a lookup field to each instructor line that indicates whether the instructor is not teaching any classes for the semester.