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CHAPTER 34

Introduction to
Developer/2000

IN THIS CHAPTER

  • What Is Developer/2000? 832
  • Why Use Developer/2000? 833
  • Features of Developer/2000 834
  • Common Tool Set Features 835

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Oracle released the first generation of its front-end development tools with version 5.0 of its RDBMS. These products were known as SQL*Forms 2.0 and RPT. Although these tools are primitive by today's standards, they were a great advance for developers of applications to access this powerful database management system. As more features were added to the RDBMS through versions 5.1, 6.0, 7.0, 7.1, 7.2, and now Oracle 7.3, the front-end tools also evolved into the product that is now called Oracle Developer/2000.

What Is Developer/2000?

Developer/2000 primarily consists of three distinct products: Oracle Forms 4.5, Oracle Reports 2.5, and Oracle Graphics 2.5. You can use these products individually or as an integrated application development platform. Although each has a separate purpose, many similarities enable you to create consistent and powerful applications.

Oracle Forms 4.5

Oracle Forms 4.5 is a tool that you can use to enter, access, change, or delete data from an Oracle database in a form-based environment. Unlike using conventional third-generation programming languages, you do not write a program that presents and manipulates the data. Instead, you build an Oracle Forms application by creating on-screen objects that are containers representing the data elements in the database. You then place these objects on the form with a graphical layout editor.

Based on selected activities called events, you can write triggers and program units to define the process to be executed whenever the event occurs. Oracle Forms 4.5 uses the concepts of
object-oriented programming (OOP) with object inheritance, reusability, and encapsulation, as well as modularity and polymorphism. These features enable you to construct high-quality , mission-critical applications in a very short time.

Oracle Reports 2.5

Oracle Reports 2.5 is used primarily to produce reports from data in the Oracle database. You can construct a report in the designer with a structured WYSIWYG ("what you see is what you get") layout editor based on a data model that you create. You build this data model using the data model editor by defining a related set of database queries and break levels.

You can include procedural constructs to provide additional functionality for data formatting and display filters. Additionally, this tool provides several useful functions that you can use to calculate summary information (such as totals or averages) at the various break levels. You can also use Oracle Reports 2.5 to execute database maintenance functions, although you can usually find better tools to perform these tasks .

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Oracle Graphics 2.5

Oracle Graphics 2.5 is used to graphically display Oracle data in a chart. These charts can be any of several types (for example, pie or bar charts) and are based on the data returned from a query. Although Oracle Graphics produces these charts in a stand-alone mode, the true power of this tool is as an OLE 2 server application that can be incorporated into OLE container applications such as Visual Basic, Excel, and, of course, Oracle Forms and Oracle Reports.

Why Use Developer/2000?

The Oracle Developer/2000 tool set requires a lot of resources! The version that runs on an IBM-compatible Windows 3.x, Windows 95, or Windows NT PC requires at least 16MB of RAM, with an additional permanent swap file of at least 8MB to design any new application modules. (It is possible to run most Oracle Developer/2000 applications on a smaller machine, but highly complex modules still perform poorly on a lesser system.) Loading all the tools with demos and online documentation requires nearly 200MB of hard disk storage. This does not include Windows, DOS, or any other software, not to mention the applications that you need to develop.

With such an abundance of tools available that interface with Oracle databases (such as Power Objects, PowerBuilder, Visual Basic, and so on), why should you choose to use Developer/2000?

When you work with small tables with few joins, a less powerful, easier-to-use tool might be acceptable. However, if application performance is a critical factor, the Oracle Developer/2000 tools provide, by far, the best mechanisms for performance tuning.

Oracle Forms provides several mechanisms that help ensure that an application provides consistently reliable data maintenance and presentation. With a few lines of code (or in some cases, by selecting appropriate object properties), you can construct a module based on several related tables with the applicable propagation of changes whenever maintenance occurs. You can use these master-detail constructs to ensure that data integrity is preserved throughout the application.

Another important concept that is "automatic" in Oracle Forms is row-level data locking. This ensures that more than one user cannot update the data at the same time and prevents arbitrary changes from occurring. These seemingly minor features are the essential ingredients necessary for enterprisewide database systems.

The Power Objects tool (also produced by Oracle Corporation) is powerful enough for many query-only applications or for small single-table maintenance applications. This tool is
syntactically compatible with Visual Basic and therefore is easy to use. However, in building a menu-driven integrated application with the complexity necessary for enterprisewide data processing, Power Objects falls short. Additionally, you must explicitly code data locking and master-detail propagation to ensure proper integrity.

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Visual Basic (a Microsoft product) can access Oracle databases using ODBC connectivity. Visual Basic has an advantage over Oracle Forms because it is a more mature product and therefore offers the availability of more add-on components . The primary disadvantage of Visual Basic is its lack of support for data integrity issues.

PowerBuilder (produced by Powersoft) has several features that are not found in the Oracle tools. The most significant of these is its capability to provide queries that can be defined
dynamically at runtime. However, PowerBuilder was written to support the Watcom SQL database engine and therefore lacks direct support for Oracle's data integrity. Another disadvantage of PowerBuilder is that, in most cases, you must write significantly fewer lines of code using Developer/2000 when accessing an Oracle database.

Features of Developer/2000

What truly puts Developer/2000 ahead of the other development products for Oracle databases is its features. These features enable the knowledgeable developer to rapidly deliver powerful, complex application units that can serve the diverse needs of the users of an enterprise database system.

All the development tools provide a similar point-and-click interface for constructing application components. This interface follows standard Windows-compliant conventions to ensure ease of use. By manipulating a mouse cursor, you can select, copy, move, and delete the elements that combine to make up an individual module. The primary common elements of this interface are

  • The ObjectNavigator, which presents a hierarchical view of all the objects that combine to form an application unit. By selecting the item in the Object Navigator, you can view and update the object's properties as well as the appearance of the object on the screen.
  • The Layout Editor, which enables the developer to place objects onto the end-user screen or report so that he or she can view the final product layout as it evolves. Functions are provided for aligning, stacking, and distributing objects, as well as defining the size and appearance of each item.
  • Various 3D buttons that you can use to perform functions such as opening and saving application units and adding, copying, or deleting objects and object properties. Other buttons are used to run the application, toggle debugger mode, and expand or contract levels in the Object Navigator.

As objects are added to a unit, the Developer/2000 tools use intelligent defaulting to define the properties of the object based on the context in which it is used. This feature enables you to construct simple default modules with practically no programming. In many cases, you can perform routine database table maintenance according to predefined general rules without any special programming.

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Oracle Unleashed
Oracle Development Unleashed (3rd Edition)
ISBN: 0672315750
EAN: 2147483647
Year: 1997
Pages: 391

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