Introduction to PowerBuilder

How to Use a DataWindow?

There are five steps involved in creating and using a DataWindow in your application:

• Select a data source and a presentation style. In other words, the way data is to be retrieved from a database and the format in which the data should be displayed.
• Define appropriate SQL statements�such as SELECT statement or stored procedure name with necessary arguments�to provide information to the user; this is referred to as the 'Data Source' definition. For example a SELECT statement to retrieve all product information.
• Paint the DataWindow (define fonts, colors, location of each field, etc.) to appropriately display the information.
• Associate the DataWindow object with a DataWindow control (you have learned about this control in the window painter) on a window/user object or a DataStore, so that the data held in the object can be displayed to the user.
• Write PowerScript statements, functions to act on the DataWindow control/DataStore.

The above diagram illustrates how PowerBuilder uses a data source, DataWindow objects, DataWindow controls and the user interface:

Although the DataWindow object contains all the definitions, it itself can't retrieve data at run-time without placing it in a DataWindow control or DataStore. DataWindow control is a container for the DataWindow object and has events where you can write script to manipulate the DataWindow object using DataWindow control's functions. You act on a DataWindow object via DataWindow control or a DataStore.

DataWindow object is independent of any DataWindow control and can be associated with any number of controls. The DW and DataWindow object association can be changed dynamically at run-time.

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