Re: [Zope3-dev] Re: Catalog improvements

[Martijn Faassen]

Dieter Maurer wrote:

Martijn Faassen wrote at 2005-8-25 13:49 +0200:


... AdvancedQuery ...
I need to figure out the lazy sorting concept too and how to port it to 
the Zope 3 catalog... I see elsewhere in the thread you also mention it 
supports a simple form of joins, which is also very interesting.


No, "AdvancedQuery" does not support joins.

But, Python is a very powerful gluing language which allows you
to implement simple joins yourself.


Okay, I misunderstood then. Of course Python allows one to implement 
joins oneself. :) I don't think we want everybody to write their own 
joins, though. It certainly cost me some headscratching thinking about 
it, especially how to do it efficiently and express it compactly, and it 
would be good if we could come up with a reasonably efficient solution 
(using indexes?) in the Zope 3 core. We could even start it out as not 
being very efficient -- it would already be useful to have an 
abstraction present and we can always make it more efficient in the future.


Regards,

Martijn
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[Zope3-dev] Re: Catalog improvements

[Dieter Maurer]

Martijn Faassen wrote at 2005-8-25 13:49 +0200:
> ... AdvancedQuery ...
>I need to figure out the lazy sorting concept too and how to port it to 
>the Zope 3 catalog... I see elsewhere in the thread you also mention it 
>supports a simple form of joins, which is also very interesting.

No, "AdvancedQuery" does not support joins.

But, Python is a very powerful gluing language which allows you
to implement simple joins yourself.


-- 
Dieter
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Re: [Zope3-dev] Re: Catalog improvements

[Garanin Michael]

  
Hello!
Not for a long time i implement sqlcatalog for storage indexes in rdms:
http://garanin.objectis.net/sqlcatalog.tar.gz 
only doc-test available: http://garanin.objectis.net/README_EN.txt 





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[Zope3-dev] Re: Catalog improvements

[Martijn Faassen]

Dieter Maurer wrote:

Martijn Faassen wrote at 2005-8-24 12:27 +0200:


...
Underfeatured query API
---


[snip]

Fast, easy batching/sorting
---

[snip]


You may have a look at "AdvancedQuery"

  

It uses Python classes to contruct queries with "&" ("and"), "|" ("or")
and "~" ("not") out of elementary classes.


It solves the batching "problem" by means of lazy sorting.
This way, you can use any batching, the catalog does not need
to know about it.


Thanks for the link. I think that I, without knowing much about advanced 
query, implemented something quite similar for Zope 3, without all the 
cool features like lazy sorting. :)


I definitely will look at AdvancedQuery when I have time, seeing whether 
we can port this (or concepts in it).


I need to figure out the lazy sorting concept too and how to port it to 
the Zope 3 catalog... I see elsewhere in the thread you also mention it 
supports a simple form of joins, which is also very interesting.


Regards,

Martijn
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