About DataWindow objects
A DataWindow object is an object that you use to retrieve,
present, and manipulate data from a relational database or other
data source (such as an Excel worksheet or dBASE file).
DataWindow objects have knowledge about the data they are
retrieving. You can specify display formats, presentation styles,
and other data properties so the data is used in the most meaningful
way by users.
DataWindow object examples
You can display the data in the format that will best present
the data to your users.
Edit styles
If a column can take only a small number of values, you can
have the data appear as radio buttons in a DataWindow object so
users know what their choices are.
Display formats
If a column displays phone numbers, salaries, or dates, you
can specify the format appropriate to the data.
Validation rules
If a column can take numbers only in a specific range, you
can specify a simple validation rule for the data, without writing
any code, to make sure users enter valid data.
Enhancing DataWindow objects
If you want to enhance the presentation and manipulation of
data in a DataWindow object, you can include computed fields, pictures,
and graphs that are tied directly to the data retrieved by the object.
How to use DataWindow objects
Before you can use a DataWindow object, you need to build
the object. To do that you can go to the DataWindow painter, which
lets you create and edit DataWindow objects. It also lets you make
PSR (Powersoft report) files, which you may want to use in applications
too. A PSR file contains a report definition–essentially
a nonupdatable DataWindow object–as well as the data contained
in that report when the PSR file was created.
This section describes the overall process for creating and
using DataWindow objects. You can use DataWindow objects in client/server,
Web-based, and multitier applications. For more information about
using DataWindow objects in different kinds of applications and
writing code that interacts with DataWindow objects, see the DataWindow
Programmer’s Guide
.
To use DataWindow objects in an application:
-
Create the DataWindow object using
one of the DataWindow wizards on the DataWindow tab page of the
New dialog box.The wizard helps you define the data source, presentation
style, and other basic properties of the object, and the DataWindow
object displays in the DataWindow painter. In this painter, you
define additional properties for the DataWindow object, such as
display formats, validation rules, and sorting and filtering criteria.For more information about creating a DataWindow
object, see “Building a DataWindow object “. -
Place a DataWindow control in
a window or user object.It is through this control that your application communicates
with the DataWindow object you created in the DataWindow painter. -
Associate the DataWindow control with the DataWindow
object. -
Write scripts in the Window painter to manipulate
the DataWindow control and its contents.For example, you use the PowerScript Retrieve function to
retrieve data into the DataWindow control.You can write scripts for the DataWindow control to deal with
error handling, sharing data between DataWindow controls, and so
on.
Reports versus DataWindow
objects
The reports you create in InfoMaker and the DataWindow objects
you create in PowerBuilder are the same objects. When you create an
InfoMaker report, you are actually creating a DataWindow object
that you can open and modify in the DataWindow painter. However,
a report is not updatable and can only be used to present data.
For information about how you can specify whether users can update
the data in a DataWindow object, see Chapter 20, “Controlling Updates in DataWindow Objects.”