How xaceclient handles recursive specification of data

Richard Durbin rd at sanger.ac.uk
Thu May 11 08:00:49 EST 2000


> In the HTML document entitled "Syntactic Definitions for the 
> ACEDB Data Base Manager", I learned that constructed types allow
> a recursive specification of data in models.  An example of this
> is in the Paper class.  There is a label called In_book whose
> type is #Paper.  As constructed types are "grafted" onto the 
> current class, this creates a potentially infinitely long class.
> This of course isn't a problem in terms of actual storage of data, 
> as the In_book label won't exist for some paper.  However,
> I was curious how xaceclient would deal with the visual
> display of the creation of a new Paper object.  Maybe I'm not
> doing something correctly, but no "In_book" label comes up, 
> and I checked the models file and found it there.
> 
> I'd like to know how this is supposed to work, since I'm writing 
> a web interface to a particular installation of ACEDB and 
> I'm going to have to solve the same problem.  

It should work by showing the #Paper in green, rather than the places
in the model that you can add data which are in blue.  When you double
click on the green #Paper cell, it will expand out into another
(empty) model, with blue places you can add data and a new green
#Paper cell that you can double click on again if neede, and so on
recursively as long as you want (but never infinitely).

I don't know why this didn't work for you - I assure you it has worked
in general for a long time.  Perhaps you changed the models and did
not "Read Models" explicitly from the main window menu.  Models are
not updated from scratch when you restart the program.

Richard







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