Delivery-Date: Wed Nov 19 22:15:56 2008
Message-Id: <200811200613.mAK6D8D8015729@bourbon.usc.edu>
To: cs551@merlot.usc.edu
Subject: Re: Search & Store
Date: Wed, 19 Nov 2008 22:13:08 -0800
From: Bill Cheng <william@bourbon.usc.edu>

Someone wrote:

  > I have a few questions regarding the search/store operations:
  > 
  > 1) If we type the same store command thrice, would we have multiple
  > instances of those bitvectors in our index structures, or do we have
  > to determine if we have already stored that file earlier and discard
  > it ?

Please see my message with timestamp "Sun 16 Nov 20:25".

  > 2) In keyword based searches, it has been mentioned that the keyword
  > searches are an "AND" based search. But in the grading guidelines,
  > consider the following cases:
  > 
  >            1. store chess.jpg 1 categories="audio mp3" artist="Blondie"
  >            2. search keywords=mp3  ......... should get a response
  > 
  >            So how is it returning a hit here when it is an "AND" based
  > search ? Should it return a hit only if all the keywords i.e.
  > categories audio mp3 artist Blondie are entered ?

The "AND" based search applies when you enter multiple
keywords *in your search command*.  So, if you enter:

    search keywords="mp3 blondie"

you should get a hit.  But if you enter:

    search keywords="mp3 song"

you should not get a hit.

  > 3) Assuming that we get a 'hit' in the second case for 'mp3' , it will
  > return all the files that has the keyword 'mp3' right ?

For a single keyword search, yes.  For a two-keyword search,
it should return all files that has *both* the keywords.
--
Bill Cheng // bill.cheng@usc.edu <URL:http://merlot.usc.edu/william/usc/>