Introduction to Delphi

             Borland Delphi is a development tool for Windows applications. It has become popular because it is as easy to use as Visual Basic and yet as powerful as C++. The programming language is an enhanced version of Pascal that supports OOP (Object Oriented Programming).

All the common parts of the Windows graphical user interface, like forms, buttons and lists objects, are included in Delphi as components. This means that you don't have to write any code when adding them to your application. You simply draw them onto your form like in a paint program.

The main thing with all these components is that code is reusable. You don't have to spend so much time on the common programming tasks of your project, but can instead concentrate on the details. This does not only make your application development faster, it also gives you a better overview of your project.

 Object Oriented Development

Most software development professionals agree that object oriented tools provide the most flexible and stable environment for creating software. Object orientation allows a developer to design and construct software-using methods that are closer to human comprehension than any other method.

Many languages support object oriented development, indeed C++ is the most common, but it is an inelegant, complex and difficult language. Delphi's Object Pascal is a much simpler language and thus easier to learn. It also has database support built-in along with a diverse set of components.

Delphi supports all the major object oriented concepts including polymorphism and inheritance. Additionally, through encapsulation, it hides the complexity of developing Windows software without compromising flexibility. Lastly, through the concept of re-use, new Windows components can be created easily and safely.

Rapid Application Development (RAD)

Delphi supports a method for developing software known as Rapid Application Development, or RAD. RAD enables software developers and the users of the software to work together closely to create a complete software system in a short period of time.

Rapid Development Tools

             Developers utilize tools which can rapidly implement changes to enable incremental prototyping. These may include CASE environments, 4GLs, DBMSs and GUI builders such as Delphi. Such tools can be used at JAD meetings enabling changes to be made in-situ.

Joint Application Development (JAD)

Small development teams consisting of users and developers meet at JAD 'workshops’, away from business and developer environments. Here they develop requirements and jointly develop deliverable portions of the system in a highly interactive manner.

Time boxing

RAD project control involves prioritizing development and defining delivery deadlines. If schedules begin to slip, rather than increasing the deadline, requirements are adjusted accordingly.

Incremental Prototyping

After some initial JAD sessions, developers can often construct a `working model' to demonstrate to users. Users then discuss enhancements and amendments that are implemented by the developers. This cycle is repeated until users are satisfied with the system.

Highly Interactive - Low Complexity Projects

Certain types of projects lend themselves to RAD more readily. These include highly interactive applications with a clearly defined user base and which are not computationally complex. Small desktop databases and consumer software is considered suitable whereas large distributed information system are considered too complex for RAD methods.