Re: Demo: Modelling Cost of Travel Paths Between Towns

"Neo" <neo55592_at_hotmail.com> wrote in message news:4b45d3ad.0411141723.6847ab83_at_posting.google.com...
> > Sounds like your DB cannot do arithmetic like SQL:
>
> That is true, TM/XDb2 does not have much to do with operations (except
> possibly intersecting things, which may the basis for all other
> operations). Currently TM/XDb2 does not know integers, floats, or how
> to add/subtract. These have to be provided by user's code just as that
> for other classes such as person, car, color, etc.
>
> > update people set age=age+1 where name='john' ; Too bad.
>
> While TM/XDb2 does not have built-in operations such as the above,
> user can easily create code that will update the age of any thing
> whose name is john and has an age, including that of things whose
> class is unknow at design-time (ie a person, dog, cat, pig, plane, etc
> in the future). Try coding that in RM.
>

It doesn't get a whole lot easier:

UPDATE your_table
SET age = age + 1
WHERE name = 'john'
AND age IS NOT NULL
; Received on Mon Nov 15 2004 - 09:01:25 CST