[tmql-wg] Negation in the different TMQL candidates

[Rani Pinchuk]

> TMPath has default "existence"  quantification in "=" and "!=" 
> operators.  Both operators are applied to sequences which are already 
> "generated" by TMPath expressions.
> 
> "!=" is true if there is at least one element in left sequence and at 
> least one in right sequence which are not equal
> 
> TMPath has also explicit "every $X in ... satisfies ..."  and "some $X 
> in .... satisfies ..." expressions.
> 
> In some cases FLOR expressions are used to provide equivalent of SQL 
> left joins
> 

Hi Dmitry,

I am not sure I understand from the above how your query works:

list{
  for $Person in /topic[person;not(roleOf::author[is-author-of]/role::opus)]
  return $Person/bn::*[1]
}

I read it as follows:

For each $Person which is of type 'person', and does not play the role
'author' in an association of type 'is-author-of'... 

But where it states that it doesn't play in ANY association of that type
in that role? Or this is the default behavior in TMPath?

I suspect that the following query might be useful for me to understand 
how TMPath does things:
How can you show all the topics that play in an association with the
association type next to it? In Toma it is:

select $player, $association where $association->$role = $player;

Thanks,

Rani.





> 
> Dmitry
> 
> 
>   
> 
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