exists() Operation

 Returns true if aVariable is not null, otherwise false. See chapter NULL Values to read more about null values.

 aVariable

Can be a variable or an attribute of an object. 

set b1 = x.exists();
set b2 = myObject.myAttr.exists();

Assigns the boolean return value of operation exists() to variable b2. Returns true if the attribute myAttr of object myObject is not null.