"Welcome back, my friends, to the show that never ends, we hope you will
attend, step inside, step inside." Those words - from an old song by Emerson,
Lake and Palmer - have been floating through my head all day, ever since I
decided on the subject of my next series of articles on the DataWindow.
It was a hard decision. We've gone through five months of graphs and, while
we haven't really explored the entire subject, five months of it is enough
for anybody. It's time to move on.
The subject of the next series of articles is dynamic DataWindows. Here we're
moving well beyond the commonplace. With these articles you'll enter the dark
domain of the DataWindow master. They'll guide you on an exploration of the
inner workings of this remarkable object and allow you to do things that only
gurus can do.
Having said that, let's just dive right in. Gather 'round, dear readers... (more)
This is the second part of a two-part article. In the last article we learned
how to use the tag property to create our own microhelp and automate it. In
this article we are going to go one step further and use the tag property for
The list of items that I used the tag property for has shrunk over the years
as Sybase has tried to give us more tools. Apart from the microhelp the most
common use I had was to implement a tool tip. Now Sybase gives us a tool tip
without our having to code a pop-up window.
Luckily I don't have to have a long list of items; one more is su... (more)
This article provides a means of automating the sorting of DataWindows... not
just grid DataWindows as discussed in last month's article, but all
DataWindows, regardless of display format.
Bear in mind that we are writing programmer tools. When writing for
programmers we want to give the programmer the maximum number of options
while minimizing the programmer effort. In other words, default as much as
possible but allow the programmer to move beyond the defaults.
We have several action items to implement:
Do the housekeeping to get an application going Create a window for sorting.... (more)
Security is a must for most corporate applications. This article will give
you a starting point to designing and implementing your own. We will do it
with a table that is added to the example database and implement it in
ancestor code. The idea is that you should only have to add rows to a table
to implement your security.
The security table will provide a means to turn on and off controls and menu
items as our inherited objects are constructed.
Login_name varchar(20) PK
Application varchar(20) PK
Item_type varchar(10) PK
Item_name varchar(20) PK
Priviledge ... (more)
Every programmer knows about the IF command. It's pretty much a fundamental
part of the syntax of every computer language that has ever existed. I don't
need to explain how it works.
The DataWindow can't use the IF command though. It does, however, support an
IF(expression, TRUE, FALSE)
In its simplest form this means that if the expression evaluates to TRUE,
then whatever statement you supply for the TRUE part is executed. If not then
the FALSE part is.
Let's begin with a simple example. Let's create a DataWindow that will show
employee information. Here is the SQ... (more)