[tmql-wg] Negation in the different TMQL candidates
Wed, 31 Mar 2004 16:24:11 +0200
> 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
I am not sure I understand from the above how your query works:
for $Person in /topic[person;not(roleOf::author[is-author-of]/role::opus)]
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;
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