An answer which could solve both the AND issue and the security issue
would be to write the security into the query. 

You don't say how you are generating queries at the moment, but for a
user who has access (say) to securedproperty1 and securedproperty3 but
not securedproperty2 it should be reasonably easy to expand a simple
text query from just "foo" to "maintext:foo securedproperty1:foo
securedproperty3:foo"

Similarly you could expand "foo AND bar" to "(maintext:foo
securedproperty1:foo securedproperty3:foo) AND (maintext:bar
securedproperty1:bar securedproperty3:bar)

This could be done using a method which takes any LuceneQuery and
iterates through it looking for TermQueries and expands any TermQuery to
the requisite form. You'd have to think about RangeQueries and other
types of query I guess. You could even write this as a wrapper to the
main search method.

Otherwise you could use a HitCollector. Regarding its problem with AND,
are you saying that in standard Lucene if you do a "foo AND bar" query
across all fields "foo" and "bar" must be stored in the same field to
get a result? If so I didn't realise that, but you could also deal with
this using query expansion on boolean queries.

Hope this is helpful,
Moray

------------------------------------- 
Moray McConnachie
Director of IT    +44 1865 261 600
Oxford Analytica  http://www.oxan.com

-----Original Message-----
From: Adrian Banks [mailto:[email protected]] 
Sent: 08 September 2009 13:12
To: [email protected]
Subject: Combining hits from multiple documents into a single hit

I am trying to get a particular search to work and it is proving
problematic. The actual source data is quite complex but can be
summarised by the following example:

I have articles that are indexed so that they can be searched. Each
article also has multiple properties associated with it which are also
indexed and searchable. When users search, they can get hits in either
the main article or the associated properties. Regardless of where a hit
is achieved, the article is returned as a search hit (ie. the properties
are never a hit in their own right).

Now for the complexity:

Each property has security on it, which means that for any given user,
they may or may not be able to see the property. If a user cannot see a
property (based on its value for each article), they obviously do not
get a search hit in it. This security check is proprietary and cannot be
done using the typical mechanism of storing a role in the index
alongside the other fields in the document.

I currently have a index that contains the articles and properties
indexed separately (ie. an article is indexed as a document, and each
property has its own document). When a search happens, a hit in article
A or a hit in any of the properties of article A should be classed as
hit for article A alone, with the scores combined.

To achieve this originally, Lucene v1.3 was modified to allow this to
happen by changing BooleanQuery to have a custom Scorer that could apply
the logic of the security check and the combination of two hits in
different documents being classed as a hit in a single document. I am
trying to upgrade this version to the latest (v2.3.2 - I am using
Lucene.Net), but ideally without having to modify Lucene in any way.

An additional problem occurs if I do an AND search. If an article
contains the word foo and one of its properties contains the word bar,
then searching for "foo AND bar" will return the article as a hit. My
current code deals with this inside the custom Scorer.

Any ideas how/if this can be done?

I am thinking along the lines of using a custom HitCollector and passing
that into the search, but when doing the boolean search "foo AND bar",
execution never reaches my HitCollector as the ConjunctionScorer filters
out all of the results from the sub-queries before getting there.

Thanks,

Adrian




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