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Posted to dev@lucene.apache.org by "Michael McCandless (JIRA)" <ji...@apache.org> on 2016/08/05 16:03:20 UTC
[jira] [Commented] (LUCENE-7404) prepared query for introducing
evaluation expression in query (not fixed second comparation member)
[ https://issues.apache.org/jira/browse/LUCENE-7404?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15409624#comment-15409624 ]
Michael McCandless commented on LUCENE-7404:
--------------------------------------------
Can't you use the expressions module with function queries to get close to this?
> prepared query for introducing evaluation expression in query (not fixed second comparation member)
> -----------------------------------------------------------------------------------------------------
>
> Key: LUCENE-7404
> URL: https://issues.apache.org/jira/browse/LUCENE-7404
> Project: Lucene - Core
> Issue Type: Improvement
> Reporter: Cristian Lorenzetto
>
> Lucene is very powerfull but has a limitation very important. It is impossible to use when you want create a query where is a expression inside.
> field1: >= field2 where field1 and field2 is not possible.
> field1:= field2^2 -4 *field3
> it is pratically impossible to index statically document for this query but it is possible to do 2 things:
> 1) create a third field hidden here is saved the result.
> 2) when you use a prepared query , it is saved automatically in a different writer this info that you can save.
> Creating a prepared query lucene do all automatically for making this query using indexes.
> PS. Pay attention that fields in expression could be not only inside the current document but also in different documents/readers.
> It could be used also for join different document types(it is a subcase of the above problem).
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