[Categoricaldata_announce] newbie to FQL

[Koksa, Vit]

Hello,

Is there any discussion forum on FQL available, please? I didn't find any, so I resort to send my e-mail to this mailing list. The FQL IDE is a very interesting and user-friendly tool, it enables even people without a deep mathematical background like me to play with categories. But I don't see things, which would be obvious to the more knowledgeable people.

The questions which I have currently in mind are:

1.  The FQL sample code "Query Composition" contains the query q1: S -> T . To see how the data migration proceeds inside this query I added these two instances:

instance Delta_sm = delta sm I
instance Pi_fm = pi fm Delta_sm

What I don't understand is why both tables a3 and a4 in Pi_fm contain a record, when there is no mapping to these tables of the schema A from the tables of the schema B in the schema mapping fm.

2. How would the example given on the slide 45 of http://categoricaldata.net/fql/introSlides.pdf be encoded in FQL?
(SELECT title, isbn FROM book WHERE price > 100)
In particular and more generally I don't know how to migrate data from nodes {a, b} to nodes {a, b, aXb} where aXb is the product/join of a and b, while "preserving" the foreign keys from aXb elements to their constituent parts in a and b.

With regards.
Vit
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