I've been unable to find an explicit answer to the question how to check if a variable is null or unassigned or undefined. Like some analogue to java's if (var == null).
The variable in question is of type xsd:integer. I'm using the assign activity where I'm using oraext:lookup-table. If the (integer) value isn't found in database, then the variable remains unassigned. However, I'm out of ideas of how to check if it's still unassigned or not