Microsoft Cloud Authors: Jim Kaskade, Lori MacVittie, Andreas Grabner, Janakiram MSV, Pat Romanski

Related Topics: PowerBuilder, Microsoft Cloud

PowerBuilder: Article

Automating Your DataWindow

The IF function, green bar DataWindows, conditional properties

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 function.

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 SQL for it:

SELECT employee_a.emp_id,  
employee_b.emp_fname manager_first_name,  
employee_b.emp_lname manager_last_name,  
employee_a.emp_fname employee_first_name,  
employee_a.emp_lname employee_last_name,  

FROM employee employee_a,  
employee employee_b,  
WHERE ( employee_a.dept_id = department.dept_id ) and 
( employee_a.manager_id = employee_b.emp_id )  
ORDER BY department.dept_name ASC,  
employee_a.emp_lname ASC,  
employee_a.emp_fname ASC

We will use this to show employee information and to show the manager's name of the employee (that's the employee_b part. Also notice that I named the employee and manager names so that I won't get confused when I get back to the DataWindow painter.

Also notice that I am sorting first by department name then the name of the employee. The reason for this will become obvious later.

Let's Start with a Green Bar
We have a lot to work with here. First there will be quite a few rows. When you have a lot of rows it becomes hard to keep your eye on one row as you go across the screen. It's easy to make mistakes. Green bar paper was meant to help that. Green bar paper is paper that has green bars printed across it. Those green bars help the eye stay on whatever row it's seeing.

In other words, green bar paper helps the reader keep on the same line.

That could come in handy for us. We don't have to use green for the color and in fact I've always liked to use a pale yellow. That way the color doesn't get in the way of the text. We can still use colors for the text and use the yellow to line up the data.

We create our DataWindow using the SQL given above. The first thing that I do is delete everything from the surface of the DataWindow. A Ctrl-A (for all) and then the delete key handles that quite nicely.

Now for the Pale Yellow
We need a custom color. The lightest of the yellows is not pale enough. Colors are defined by Red, Green, and Blue. Each of the colors can be a value of 0 (complete lack) to 255 (brightest). If you want a bright red that would be 255, 0, 0. If you want white that would be 255, 255, 255. Black would be 0, 0, 0. All of the dark colors would be half of 255.

If you think about it you can come up with a lot of different shades. Since yellow is red and green we want full red, full green, and 75% blue. That would be 255 * .75 or 191. There's no need to be concerned with fractions here.

Go to Design in the menu then select Custom Colors.

Notice where the figure says to click there first. That way you define where your custom color goes. Once you've selected that go over to the right and type in your values for red, green, and blue. Now you have a custom color that you can use forever. Of course you can change that color any time but since you have 16 custom colors you can probably have all your favorites there.

Back to the DataWindow
Okay, now we have a DataWindow from which we have deleted everything. To do the green bar we need a rectangle object. Simply place it on the screen and stretch it out to be as long as you think the row will be. Set the foreground and background colors to be your new pale yellow custom color. Make sure that the rectangle is taller than your row will be. You will eventually slide the detail band up to cover it.

Take a look at Figure 2. You should move the rectangle as close to the top of the detail band as you can. Here's a hint. Select the rectangle by clicking on it. Drag it all the way to the left. Then, using the up arrow, move it toward the top of the detail band one keystroke at a time. Eventually you will hit the up arrow and the rectangle will vanish. It has gone into the header band. Hit a down arrow and it comes back. It will then be as close to the top as possible.

Figure 2 points out that you should leave some space between the bottom of the rectangle and the detail band. We will move the detail band up later, making the rectangle neatly fill the entire detail area.

The next step is to implement the green bar. What we will do is have the rectangle be invisible on every other line. It really doesn't matter whether the rectangle is visible on the even or odd lines. I guess it's a matter of choice. Personally, if we are going to have column headers I like to start with the rectangle. That way we don't have a large white area at the top.

Again, it doesn't really matter though.

How do we do this? We find the visible property of the rectangle. If that property is 1, then the rectangle is visible. If it is 0 then it's not.

That means that we need the IF function. It needs to be:

IF(odd_row, 1, 0)

That's not so bad. If the row is an odd number, set the visible property to 1, otherwise to 0.

The next question is how in the world do we find out if the row is odd? Well, there is a function that we can use called Mod(x, y). The x is the number that you want to divide by y. The y is the number you want to divide into x. Mod will return the remainder of the operation.

For example, mod(13, 4) will return 1. 13 / 4 = 3 with a remainder of 1.

If we can know the current row we can use a mod(currentRow(), 2). If this returns a 1, the row is odd. Otherwise it's even.

Figure 3 shows you the properties for the selected rectangle. You can see that the Visible property is circled. See the little button to the right of it? Whenever you see one of those the property can have an expression. Click on that button.

Now look at Figure 4. It shows the dialog that you use to create your expressions. Notice that we are setting the expression for the rectangle. I also wanted to point to the list of available functions. You can see the CurrentRow() function in the list of functions. In our case I am showing you where I got it. The Mod function (which I also used) is farther down in the list but it's there.

Over to the bottom right you can see a list of all of the columns in the DataWindow. If we wanted to we could make the visibility of the rectangle dependent on the value of one of the columns. For example, we could have said:

if(employee_status = 'L', 1, 0)

In that case the rectangle would only be visible for every employee that was on leave. In fact, since there are three possible statuses of each employee we could have three different rectangles, each with a different color and set each dependent on the status. That way our DataWindow would show a different background for each status.

Let's not do that though.

What we did was to use a function that would allow us to turn on the rectangle for odd numbered rows and turn it back off for even rows. Let's look at that expression:

if(mod(getrow(), 2) = 0, 0, 1)

The getRow provides us with the current row. The mod function will return the remainder of the getRow() / 2. Thus, for row 1 we will get:

if(mod(1, 2) = 0, 0, 1

for row 2 we will get:

if(mod(2,2) = 0, 0, 1)

This will result in us getting a visible rectangle for every other row. That's exactly what we wanted. Now we can populate our DataWindow with the columns that we want in the order that we want. I really like using computed fields for columns that I don't intend the user to change, especially names. So my first column will be the user name. I set that up as a computed field.

employee_employee_last_name + ', ' +  employee_employee_first_name

Now the name will be properly formatted (see Figure 5).

That looks a lot better than putting the two names on the DataWindow and having a variable space between the first and last.

Now let's put the manager on the DataWindow. The expression for that would be:

'Manager: ' +  employee_manager_last_name + ', ' +  employee_manager_first_name

Let's use the status of the employee. If the employee is terminated let's make their name red. If they are on leave, let's make them gray. If they are active, let's leave it black.

To do this we need to do an expression for the foreground color of the name computed field. Select that computed field then in the properties find the foreground color. In case you are having problems I will provide help (see Figure 6).

The expression for that will be a lot more complex. We will need to use another function called RGB.

The RGB function takes three arguments, each of which are integers from 0-255. They are, in order, Red, Green, and Blue.

Here will be the expression. I know it looks complicated but don't worry, we'll take it apart.

if( employee_status = 'A', 0, if( employee_status = 'L', RGB(127,127,127), RGB(255,0,0)))

This says, if the employee status is A (active) then the color will be 0. That would be black. The FALSE part of the IF function is another IF function. This one says that if the employee status is L, the color needs to be 127,127,127. That means each of the colors is only half bright. This gives us gray. Otherwise, if the employee status is anything other than A or L, it should be bright red.

That's all there is to it. This will serve us very well.

There's usually more than one way.

We could make this easier to code and easier to maintain. Expressions can use global functions so we could write a function like the following:

Long f_status_color(string as_status)
choose case UPPER(as_status)
case "A"
return 0
case "L"
return RGB(127, 127, 127)
case else
return  RGB(255, 0, 0)

Then replace that complex if function with the following:

f_status_color( employee_status )

That is so much easier. The only down-side is that if you make a habit of this, you wind up with a lot of functions. Of course you could put them all in their own PBL and they would be out of the way.

Are we done yet?

Well, not really. We haven't done anything with the department. We have sorted by the department so let's create a control break on the department.

Control Break is what we called a Group back in the days when I went to college. Select Rows and Create Group from the menu, then drag the Department Name over to the Columns as in shown in Figure 7.

Now all we have to do is throw the DataWindow into a window, add two lines, one to set the transaction object and the other to set retrieve the DataWindow and we are done (seem Figure 8). Most of the functionality is inside the DataWindow, right where it should be.

More Stories By Richard (Rik) Brooks

Rik Brooks has been programming in PowerBuilder since the final beta release before version 1. He has authored or co-authored five books on PowerBuilder including “The Definitive DataWindow”. Currently he lives in Mississippi and works in Memphis, Tennessee.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.

@ThingsExpo Stories
In his keynote at 19th Cloud Expo, Sheng Liang, co-founder and CEO of Rancher Labs, will discuss the technological advances and new business opportunities created by the rapid adoption of containers. With the success of Amazon Web Services (AWS) and various open source technologies used to build private clouds, cloud computing has become an essential component of IT strategy. However, users continue to face challenges in implementing clouds, as older technologies evolve and newer ones like Docke...
WebRTC sits at the intersection between VoIP and the Web. As such, it poses some interesting challenges for those developing services on top of it, but also for those who need to test and monitor these services. In his session at WebRTC Summit, Tsahi Levent-Levi, co-founder of testRTC, reviewed the various challenges posed by WebRTC when it comes to testing and monitoring and on ways to overcome them.
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life sett...
SYS-CON Events announced today that Coalfire will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Coalfire is the trusted leader in cybersecurity risk management and compliance services. Coalfire integrates advisory and technical assessments and recommendations to the corporate directors, executives, boards, and IT organizations for global brands and organizations in the technology, cloud, health...
@ThingsExpo has been named the Top 5 Most Influential M2M Brand by Onalytica in the ‘Machine to Machine: Top 100 Influencers and Brands.' Onalytica analyzed the online debate on M2M by looking at over 85,000 tweets to provide the most influential individuals and brands that drive the discussion. According to Onalytica the "analysis showed a very engaged community with a lot of interactive tweets. The M2M discussion seems to be more fragmented and driven by some of the major brands present in the...
The Internet of Things (IoT), in all its myriad manifestations, has great potential. Much of that potential comes from the evolving data management and analytic (DMA) technologies and processes that allow us to gain insight from all of the IoT data that can be generated and gathered. This potential may never be met as those data sets are tied to specific industry verticals and single markets, with no clear way to use IoT data and sensor analytics to fulfill the hype being given the IoT today.
SYS-CON Events announced today that Transparent Cloud Computing (T-Cloud) Consortium will exhibit at the 19th International Cloud Expo®, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. The Transparent Cloud Computing Consortium (T-Cloud Consortium) will conduct research activities into changes in the computing model as a result of collaboration between "device" and "cloud" and the creation of new value and markets through organic data proces...
SYS-CON Events announced today that MathFreeOn will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. MathFreeOn is Software as a Service (SaaS) used in Engineering and Math education. Write scripts and solve math problems online. MathFreeOn provides online courses for beginners or amateurs who have difficulties in writing scripts. In accordance with various mathematical topics, there are more tha...
More and more brands have jumped on the IoT bandwagon. We have an excess of wearables – activity trackers, smartwatches, smart glasses and sneakers, and more that track seemingly endless datapoints. However, most consumers have no idea what “IoT” means. Creating more wearables that track data shouldn't be the aim of brands; delivering meaningful, tangible relevance to their users should be. We're in a period in which the IoT pendulum is still swinging. Initially, it swung toward "smart for smar...
@ThingsExpo has been named the Top 5 Most Influential Internet of Things Brand by Onalytica in the ‘The Internet of Things Landscape 2015: Top 100 Individuals and Brands.' Onalytica analyzed Twitter conversations around the #IoT debate to uncover the most influential brands and individuals driving the conversation. Onalytica captured data from 56,224 users. The PageRank based methodology they use to extract influencers on a particular topic (tweets mentioning #InternetofThings or #IoT in this ...
SYS-CON Events announced today that SoftNet Solutions will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. SoftNet Solutions specializes in Enterprise Solutions for Hadoop and Big Data. It offers customers the most open, robust, and value-conscious portfolio of solutions, services, and tools for the shortest route to success with Big Data. The unique differentiator is the ability to architect and ...
SYS-CON Events announced today that Niagara Networks will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Niagara Networks offers the highest port-density systems, and the most complete Next-Generation Network Visibility systems including Network Packet Brokers, Bypass Switches, and Network TAPs.
SYS-CON Events announced today that Embotics, the cloud automation company, will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Embotics is the cloud automation company for IT organizations and service providers that need to improve provisioning or enable self-service capabilities. With a relentless focus on delivering a premier user experience and unmatched customer support, Embotics is the fas...
In an era of historic innovation fueled by unprecedented access to data and technology, the low cost and risk of entering new markets has leveled the playing field for business. Today, any ambitious innovator can easily introduce a new application or product that can reinvent business models and transform the client experience. In their Day 2 Keynote at 19th Cloud Expo, Mercer Rowe, IBM Vice President of Strategic Alliances, and Raejeanne Skillern, Intel Vice President of Data Center Group and ...
Virgil consists of an open-source encryption library, which implements Cryptographic Message Syntax (CMS) and Elliptic Curve Integrated Encryption Scheme (ECIES) (including RSA schema), a Key Management API, and a cloud-based Key Management Service (Virgil Keys). The Virgil Keys Service consists of a public key service and a private key escrow service. 

Data is the fuel that drives the machine learning algorithmic engines and ultimately provides the business value. In his session at Cloud Expo, Ed Featherston, a director and senior enterprise architect at Collaborative Consulting, will discuss the key considerations around quality, volume, timeliness, and pedigree that must be dealt with in order to properly fuel that engine.
Fifty billion connected devices and still no winning protocols standards. HTTP, WebSockets, MQTT, and CoAP seem to be leading in the IoT protocol race at the moment but many more protocols are getting introduced on a regular basis. Each protocol has its pros and cons depending on the nature of the communications. Does there really need to be only one protocol to rule them all? Of course not. In his session at @ThingsExpo, Chris Matthieu, co-founder and CTO of Octoblu, walk you through how Oct...
Fact is, enterprises have significant legacy voice infrastructure that’s costly to replace with pure IP solutions. How can we bring this analog infrastructure into our shiny new cloud applications? There are proven methods to bind both legacy voice applications and traditional PSTN audio into cloud-based applications and services at a carrier scale. Some of the most successful implementations leverage WebRTC, WebSockets, SIP and other open source technologies. In his session at @ThingsExpo, Da...
In past @ThingsExpo presentations, Joseph di Paolantonio has explored how various Internet of Things (IoT) and data management and analytics (DMA) solution spaces will come together as sensor analytics ecosystems. This year, in his session at @ThingsExpo, Joseph di Paolantonio from DataArchon, will be adding the numerous Transportation areas, from autonomous vehicles to “Uber for containers.” While IoT data in any one area of Transportation will have a huge impact in that area, combining sensor...
If you had a chance to enter on the ground level of the largest e-commerce market in the world – would you? China is the world’s most populated country with the second largest economy and the world’s fastest growing market. It is estimated that by 2018 the Chinese market will be reaching over $30 billion in gaming revenue alone. Admittedly for a foreign company, doing business in China can be challenging. Often changing laws, administrative regulations and the often inscrutable Chinese Interne...