Is it not true for any RDBMS table as well which does not have a Primary Key? If this is a problem that you are facing, then it can be solved by introducing one unique identifier as a field in your index which would act as a Primary Key for your index. Using an untokenized field might not be a good idea in some cases. :)
Also, the deleteDocuments(term[]) function then gives the added flexibility of identifying and deleting more that one documents (by a single function call) identified by an array of Primary Key values. kapilChhabra -----Original Message----- From: Samuel LEMOINE [mailto:[EMAIL PROTECTED] Sent: Friday, July 20, 2007 6:31 PM To: java-user@lucene.apache.org Subject: deleting/updating/identifying a document Hi everybody ! I'm asking myself about the way Lucene deals with deleting documents. As far as I know, a document is identified by a document number, but this document number is not reliable for long-term issues as it may change on segment merging. The way Lucene deletes documents' data from the index questions me, cause it relies on terms (or document number, which as told above is not reliable, and must be retrieved from a request). The methods I've found for deleting documents from the index are those from IndexWriter and IndexReader classes, deleteDocuments(term ) or deleteDocuments(term[] ). These methods deletes the index'entries containing the given term. According to the API javadoc, deleteDocuments(term[] ) will delete each file that contains at least one of the given terms: if it really works in this way, I don't really understand why it's does so. Wouldn't it be more useful if it deleted each file containing *all of* the given terms? (or maybe it'is the way it works actually?) These reflexions lead me to conclude that, in order to be able to remove the entries of a specific document in a Lucene index, we must store an untokenized field to identify each document solely. I find it strange having to use such an "artifice" to keep traces of documents independantly. It's not very impeding, it's just... strange. Any contributive thinkings on this matter are welcome :) Thanks for reading, Samuel --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
