Conditional Blocks in Cognos 8
By Craig Harding, Consultant for PerformanceG2
Conditional Blocks
The goal of this report is to prompt users on which display they would prefer, a list or a chart.
To start, create a simple list report in Report Studio. Using the Cognos sample data, product line, order method and revenue are added to the list. From the toolbox, drag and place a pie chart below the list. Select the chart and in the properties pane, attach this chart to query 1:
Now the chart can be populated from the data items tab.
The consumers of this report need the ability to choose between the displays they want to see. To accomplish this, build a blank prompt page allowing them to select from a drop down list either list or chart. Drag a value prompt to the prompt page with the following settings:
At this point hit ‘Finish”. The dropdown list has to be populated manually though the static choices property of the value prompt. The two choices added are list and chart.
*You can leave the display value blank. If you do so, Report Studio is smart enough that it will take the use value for the display value.
Now that my prompt page is set, return to the Report Page. In order to conditionally display an object, use the conditional blocks object in the toolbox. Drag this to the bottom of the report.
The next step is to attach the variable to the conditional blocks block variable property. This variable is a Boolean variable that either equals a list or doesn’t.
We need to test if our parameter is equal to the value ‘List’. If the user selected List this expression will evaluate to true, if the user selected ‘Chart’ from the prompt, then this will evaluate to false.
After this step is completed there is a new property on the conditional blocks object that tell us which block we are currently looking at. First, drag the chart into the ‘No’ block.
Now, select the conditional block again, and switch the current block property to ‘Yes’. The conditional blocks object appears empty because there is currently nothing in the ‘Yes’ block.
The final step is to drag the entire list inside the ‘Yes’ block.
Now when the report is run, the user will be prompted for their display of choice.
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