String :: isNull - Determines whether the string data pointer is null.
The function returns true when no data area has been allocated for the string; otherwise returns false. In contrast to isEmpty() a String object that returns true for isNull() has definitely no coding type.
odaba::String().isNull(); // returns true
odaba::String("").isNull(); // returns false
odaba::String("x").isNull(); // returns false
odaba::String(false).isNull(); // returns false
Return value: Success ( bool )
The value is true when the function was executed successfully. Otherwise the value is set to false.