[Zope-dev] ZCatalog searching for missing values

[Bjorn Stabell]

Having an exists function would be great.  I was trying to do the same
using CatalogQuery, but I found no way to check for Missing.Value, which
is the repr() of what's in the catalog's metadata field for objects that
don't have that attribute/function.  I also ran into problems doing more
complex or'ing and and'ing, and I assume we'll have better luck with
ZOQLMethod for that.

I just tried out ZOQLMethod as well.  Couldn't get it to work, but it
looks like really solid craftsmanship.  I like the user-friendly way of
selecting base object and the complete syntax. :)  Some questions:


1. I couldn't get any query to work.  I keep getting

	exceptions.TypeError
	argument 2 to map() must be a sequence object

Here's an example query that I've tried

	SELECT id
	  WHERE title =3D=3D ''
	  RECURSIVE;


2. Is the ZCatalog searching implemented?  How do I activate it?


3. Do you have any plans to implement JOIN?


The exists function would be very cool.


Keep up the great work.  Hope this helps flush out some features :)


Bye,
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Bjorn


Stephan wrote:
[...]
> I actually need to look at Casey's code and see what I can reuse. The=20
> efficiency of my version is not that great yet, but much more=20
> flexible. So I want to take Casey's code and optimize mine a little.
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> BTW, I just added a mailing list and a poll for ZOQL. Please go to=20
> http://demo.iuveno-net.de/iuveno/Products/ZOQLMethod and vote=20
> in the poll, so I can get an estimate of the general interest.
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> >I have one question: is it possible using a normal catalog query or
> >Kavio's catalog query to check if a value is not set?  The
> >representation returned is Missing.Value, but I seem to be unable to
> >say, e.g, 'Description =3D=3D Missing.Value' etc.  How hard is it to =
add
> >such functionality?
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> You mean, whether the system checks, if a property exists at=20
> all or is set to None? I think both would be no problem.
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> 1. Property exists or not:
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> I could support a function, like: exists(Property)
> Example:
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> SELECT *
>    FROM Test
>    WHERE exists(Property);
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> 2. Property is set to None:
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> Simply use equal: Property =3D=3D None
> Note: That might work already? I have to check...
> Example:
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> SELECT *
>    FROM Test
>    WHERE Property =3D=3D None;
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> Regards,
> Stephan
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> --
> Stephan Richter
> CBU - Physics and Chemistry Student
> Web2k - Web Design/Development & Technical Project Management
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