How you can set a dimension to always have one value selected?

[#1]

QlikView has the capability of setting a dimension to always have one and only one value selected.   This is the equivalent of setting a parameter.   How can you do this in Sense?

An example of where this is required is when you have data in multiple currencies.   Suppose you have sales data where each transaction is in local currency, e.g. USD, Euros, Yen, etc.   You want to show the total sales.   It's not valid to add USD and Euros and Yen; instead they must be converted to a single currency using exchange rates and then added.  We need the ability for the user to specify the translation currency.  This specification should not filter the data, e.g., choosing USD shouldn't show only USD transactions, but must instead determine the exchange rates for each from/to combination.   The parameter always needs to be set to one currency so that the display of the totals is always valid.

If Sense does not have the "always select one" option for a dimension, how do you address the example above?  At the moment I see this as a big gap in functionality.

[petter]

There are at least two Qlik Sense extension available on Qlik Branch that could be used:

qsVariable:

Qlik Branch

Option Variable:

http://branch.qlik.com/#!/project/5719fbfa866e682d3705fab1

Then you could use the variable-value that is selected to filter the right currency to get the exchange rate that is correct.

You could also do it natively in Qlik Sense without an extension but not as elegantly:

Let the users have the title "CTRL+Click to select a single currency". The translation table could be a data island table or and then use Only() or Min() or Max() together with Set Analysis/Set Expression to get the right value.