Bob Hendry

Objects can be added to your DataWindow programmatically via a Modify statement. In my opinion, the dynamic creation of objects within a DataWindow has been a highly underused feature. Dynamically creating (or destroying) objects within a DataWindow has many advantages such as: Dynamically changing the content If a printed DataWindow varies in appearance from its visual presentation The syntax for creating objects within DataWindows can be daunting; no wonder it's not used that often. Before I go into more detail, it's important to know how objects are contained in a DataWindow in the first place. Once you understand this, you will find that dynamically creating objects is easy. The Naked DataWindow Background It should come as no surprise that a DataWindow is really just a collection of objects, each with its own properties. When a programmer is creating a DataWindo... (more)

Using DataWindow Expressions

The DataWindow has been around since the first version of PowerBuilder and is indeed the reason many shops have chosen PB. Around for over 10 years, it has remained the most powerful data control in any language. No other language has anything like it - not even Visual Basic or Java. If your application requires a complicated presentation layer containing heavy database transactions, the DataWindow is the control of choice. As PowerBuilder versions have progressed, so has the functionality of the DataWindow; most PowerBuilder programmers are aware of the basic functionality. Th... (more)

DataWindow Reporting

In my early PowerBuilder days, I was very impressed with how easy it was to create and format DataWindows for either online or printed reports. At its easiest, a simple print method is required to send a "What you see is what you get" version of the DataWindow to the printer. Even when the printed version of a DataWindow is different from the visual one, a simple ShareData() function would be all that is required. What took a while, however, was learning how to display and print reports that either had a master/detail relationship or no relationship at all. In short, what if I n... (more)

Dynamic SQL

From the beginning, the DataWindow has been a powerful client/server control. What has set it apart from competing products is its ability to create SQL. In reality, the DataWindow is a SQL-generating machine. By keeping track of row and column statuses, the DataWindow is able to generate the correct SQL statement to UPDATE, DELETE, or INSERT rows into a database. In most instances, the developer is oblivious to the SQL generation; all that's needed to unleash all this functionality is to issue a simple update function. However, DataWindows can take SQL only so far, as their use ... (more)

Mastering the JTable

JBuilder Data Express controls enable JBuilder developers to use prebuilt objects to provide the user with an interface in which to view and manipulate data. For the most part, the use of Data Express components simplifies our task of programming data access functionality into our applets/applications. One drawback of using these components is that you're restricted to using only functions and changing properties that are supported by that specific control. In other words, although JBuilder simplifies your task, you can use only prewritten functionality. What if you wanted total... (more)