EXISTS

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SYNTAX:
 
FUNCTION EXISTS ( V:GENERIC ) : BOOLEAN;
 
The exists function returns true if a value exists for the input parameter, or false if no value exists for it. The exists function is useful for checking if values have been given to optional
attributes, or if variables have been initialized.
 
has the same functionality as the xpfExists() function except when the actual argument "V" ia an INVERSE simple (not an aggregate) attribute.
 
In EDM all Inverse attribute are implemented as an aggregate. Hence, all Inverse attributes of an Entity are created when the actual object (entity instance) is created. The Exists() function will return FALSE when the actual argument "V" is an empty aggregate (the actual argument "V" is not INDETERMINATE) owned by a "simple Inverse attribute".
 
Parameters :
 V is an expression which results in any type. This parameter can only be an inverse simple attribute and not an aggregate