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<p class="MsoNormal">Hello,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">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.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The questions which I have currently in mind are:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">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:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">instance Delta_sm = delta sm I<o:p></o:p></p>
<p class="MsoNormal">instance Pi_fm = pi fm Delta_sm<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">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.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">2. How would the example given on the slide 45 of <a href="http://categoricaldata.net/fql/introSlides.pdf">
http://categoricaldata.net/fql/introSlides.pdf</a> be encoded in FQL? <o:p></o:p></p>
<p class="MsoNormal">(SELECT title, isbn FROM book WHERE price > 100)<o:p></o:p></p>
<p class="MsoNormal">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.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">With regards.<o:p></o:p></p>
<p class="MsoNormal">Vit<o:p></o:p></p>
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