Is it possible to have a hierarchy of parameters?

Question

Hi,
I need a workbook with 6 or 7 sheets, all showing data for a chosen hospital, specialty, PCT and GP practice. One sheet will show the number of outpatient referrals, another the number of outpatient attendances, another the number of inpatient admissions, etc. by month.
If I use page items for hospital, specialty, PCT and practice then the hierarchies I've set up of hospital to specialty, and PCT to practice mean that once the hospital is chosen only that hospital's specialties are shown, and once the PCT is chosen, only that PCT's practices are shown for the user to select. But the user has to select them on every sheet! Apart from being a nuisance, it would be possible for them to accidentally select different combinations on different sheets, causing confusion.
If I use parameters for hospital, specialty, PCT and practice then the user only has to enter them once, but they can accidentally select a specialty which isn't relevant for the hospital, or a practice that isn't relevant for the PCT chosen.
Neither alternative is satisfactory. So does anyone have any idea how I can use the hierarchies but also only have the users entering their choices once for the whole workbook?
Thanks,
Ros

Answer 1

Hi Ros
Yes, it looks like you answered your own question. In order for cascading parameters to work there must not be any N:N relationships in use, and there must be a list of values on each item.
Ideally there should be a hierarchy, and the hierarchy must consist of pure 1:N releationships with all of the items coming from the same folder.
If these rules can be adhered to then you can set up cascading parameters. Here is a basic workflow and remember that this can only be created in Discoverer 10.1.2 Plus:
1. Make sure that the items are coming from the same Discoverer folder and, ideally, make sure you create a hierarchy where these two items relate to each other. As a by-product this would allow regular drilling down and rolling up.
2. Make sure that there is a list of values on both items. If there is no hierarchy it will take Discoverer a lot longer to work out the list of values for the second parameter.
3. Create a condition and parameter on the highest level, at the 1 end of the 1:N.
4. Create a second condition and parameter, but before you complete the parameter check the button called "Filter the values based on the selected conditions" and then place a check alongside the first condition.
5. When you finally arrange the order of the parameters, make sure you get the user to enter a value for the first parameter before you prompt for the second parameter. The list of values for the second parameter will now be constrained by the item(s) selected for the first parameter.
6. You can repeat the above steps to have a three-item cascade if you desire.
I hope this helps
Best wishes
Michael Armstrong-Smith
URL: http://learndiscoverer.com
Blog: http://learndiscoverer.blogspot.com