About PowerBuilder
PowerBuilder is an object-centric graphical application development environment.
Using PowerBuilder, you can easily develop many types of applications. PowerBuilder provides
all the tools you need to build industrial-strength applications,
such as order entry, accounting, and manufacturing systems.
Two-tier and multitier applications
PowerBuilder applications can
be traditional graphical client/server two-tier applications
that access server databases. A traditional client/server
application is a collection of windows that contain controls that
users can interact with. You can use standard controls–such
as buttons, checkboxes, dropdown listboxes, and edit controls–as
well as special PowerBuilder controls that make your applications
easy to develop and easy to use.
You can also build multitier applications with PowerBuilder.
A multitier (distributed) application usually has a client application
that request services from a server application. For example, your
client application could request services from a PowerBuilder component
on a Jaguar CTS or MTS server.
Internet applications
PowerBuilder applications
can also be web-based. A web-based application can be originally
created for the Internet or be an existing PowerBuilder application
extended to the Internet.
For more information about Internet development using PowerBuilder,
see Using the PowerBuilder Internet Tools
.
Cross-platform development
PowerBuilder supports
cross-platform development and deployment. For example, you can
develop an application using PowerBuilder under Windows and deploy
the very same application–without changes–on UNIX.
You can even have a cross-platform team of developers, some using
Windows and some using UNIX, developing the same application at
the same time. They can freely share PowerBuilder objects used in
the application, because the objects are the same across the different
computing platforms that PowerBuilder supports.
Most of the figures in this book show PowerBuilder running on
Windows, but the PowerBuilder graphical user interface looks and works
much the same on all supported Windows and UNIX platforms.
For more information about cross-platform development using PowerBuilder, see Application
Techniques
.
About applications
In PowerBuilder you
are always working in the context of an application. When you create
an application, you name the Application object and specify an application
library for the Application object and the other objects you will create.
You can add libraries to the application. You can also select a
different application to work on. For information about applications,
see Chapter 2, “Working with Applications”.
About objects
Your application is a collection of PowerBuilder objects. As you work in your application, you
create new objects and open existing objects to continue work on
their development. For more information about objects, see “Working with objects”.
About DataWindow objects
The applications
you build are centered around your organization’s data.With PowerBuilder you
can define DataWindow objects to retrieve, display, and manipulate
data. For more information about DataWindow objects, see Chapter 14, “Defining DataWindow Objects “.
About painters
You build the objects
in your application using object editors called painters. PowerBuilder provides
a painter for each type of object you build.
For example, you build a window in the Window painter. There
you define the properties of the window, add controls such as buttons
and edit controls, and code the window and its controls to work
as your application requires.
About libraries
As you work in a PowerBuilder application,
the objects you create are stored in one or more libraries (PBL
files) associated with the application. When you run your application, PowerBuilder retrieves
the objects from the library.
PowerBuilder provides a Library painter for you to manage your
libraries. For information about creating a new library and working
with libraries in the Library painter, see Chapter 3, “Working with Libraries”.
About events and scripts
PowerBuilder applications are event-driven: users control the
flow of the application by the actions they take. When a user clicks
a button, chooses an item from a menu, or enters data into a textbox,
an event is triggered. You write scripts that specify the processing
that should happen when the event is triggered.
For example, buttons have a Clicked event. You write a script
for a button’s Clicked event that specifies what happens
when the user clicks the button. Similarly, edit controls have a
Modified event, which is triggered each time the user changes a
value in the control.
You write scripts using PowerScript, the PowerBuilder language.
Scripts consist of PowerScript functions, expressions, and statements
that perform processing in response to an event.
The script for a button’s Clicked event might retrieve
and display information from the database; the script for an edit
control’s Modified event might evaluate the data and perform
processing based on the data.
Scripts can also trigger events. For example, the script for
a button’s Clicked event might open another window, which
triggers the Open event in that window.
About functions
PowerScript provides a rich assortment of built-in functions
you use to act upon the objects and controls in your application.
There is a function to open a window, a function to close a window,
a function to enable a button, a function to retrieve data, a function
to update the database, and so on.
You can also build your own functions to define processing
unique to your application.
Creating an executable or a component
When you have completed your application, you create an executable
version to give to your users or you build and deploy your component. PowerBuilder provides
an easy way to package your application for distribution or to build and
deploy a component.