Latest News from Konstantin Goldobin

Drop-Down Lists for Decimal Fields

Fri, 13 Jan 2012 09:30:00 EST

PowerBuilder has a very handy way to make data entry more convenient: the DropDownDataWindow and DropDownListBox edit styles for DataWindow columns. Indeed, it’s much simpler to pick up a value from a look-up list than to type it in each time you need to enter it. However, it looks like we’ve overlooked one of the cases when use of a drop-down list can make data entry easier for the user. Most of the time we use drop-down lists when working with lists of pairs “encoded value”/”decoded value”: the users see and select decoded values and encoded values are saved in the database. The data type of the columns for which we use drop-down lists in such cases may be either string or integer, but it doesn’t make any difference in terms of defining the edit style. Another instance when drop-down lists come in handy is when there is a predefined list of all possible values that can be entered into a column; in this case the entered values shouldn’t even necessarily be encoded and may be stored in the database as is. In this article I will show you how drop-down lists can be used for an altogether different purpose – the entry of special values, and what you should take into consideration when using drop-down lists for DataWindow decimal columns.

The Mystery of the dbName DataWindow Column Property

Fri, 16 Jul 2010 07:30:00 EDT

PowerBuilder has very good online help and documentation that extensively covers most aspects of programming with PowerBuilder. However, from time to time you’ll come across a problem that you can’t find an answer to in the online help or documentation. If a search on the Internet does not yield any results either, the only remaining option is to try to find the answer on your own. In this article I describe a problem I had with the dbName DataWindow column property and what I found out about it. I was maintaining a project that had had no activity for quite a few months. I even had a hardware failure on the PC where the development environment was set up but didn’t really worry about this: the project was stable and there were no potential extensions in sight. But you know how it is – one day I got a call from a customer and it turned out that a small extension was needed in one of the applications. I set up the development environment on another PC and restored the source code from a backup copy. The application was written in PB6.5 with SQLAnywhere 5 used as a back end. I created the needed OBDC data sources and database profiles for PowerBuilder and successfully connected to the database. Then I decided to refresh my memory and started exploring the functions of the application around the place where the change was going to be done. Imagine my surprise when I received a runtime error after starting one of the key operations of the application. I double-checked the source code, the database, and rebuilt the project in PowerBuilder, but it was all in vain. The application didn’t work; it crashed each time I called one particular operation.

Make Your Design Ideas Speak: Using UML in PowerBuilder Projects

Wed, 15 Apr 2009 13:30:00 EDT

A picture is worth a thousand words. We all have heard this saying a countless number of times. But what if you don’t understand what is drawn in the picture? I was approached once with a request to review requirements specifications for some module. The document contained a scheme that represented the place of the module within the system. The picture was mainly made of rectangles and arrows.

Working with Legacy Applications

Tue, 26 Feb 2008 08:15:00 EST

When I was just starting my career in programming, I thought I would be creating new applications. And I did - I created a few applications from scratch. Maybe two or three of them. But for the most part what I've been doing is working with code written by someone else a while ago - legacy code. What is legacy code? You could define legacy code as ancient applications that were written in the past.

Getting Rid of Global Variables

Thu, 05 Jul 2007 13:00:00 EDT

It may seem as if PowerBuilder programmers are bound to use global variables. Even the PFC, which is said to be the most successfully designed object-oriented framework, requires the use of global variables. Is it something in the nature of PowerBuilder that makes us use them? I won't discuss whether it's good or bad to use global variables as enough has been said on this subject. However, I am going to discuss why global variables are usually used in PowerBuilder applications and how we can live without them.

Exploring DataWindow Display Formats

Wed, 14 Mar 2007 12:00:00 EDT

DataWindow display formats aren't a big secret. Most PowerBuilder developers use them to format numeric, date, time, and string values properly. Such display formats are usually straightforward and contain characters that have special meaning for a specific datatype like '#' for numeric values or '@' for string values. However, the DataWindow display format is a very powerful tool and you can get more than simple data formatting. This article explores what you can do with DataWindow display formats demonstrating a few tricks.

Highlighting Selected Text in PowerBuilder DataWindow

Thu, 17 Aug 2006 08:45:00 EDT

Let's suppose that you have a search window where a user can enter a search string and get the list of text items matching this pattern. Ideally, the portions of text that meet the search criteria should be highlighted, for example, by text formatting.