FAQ
Hi All,

I'm new to Lucene and have picked up the Lucene in Action book to get started. Really enjoying it but I have a small nagging question.

Is the index stored in the same "physical document" as the fields and values? If not, where is it stored and how is it linked.

This is because of this statement in the book

When you retrieve a document from the index, only stored fields will be present. For example, fields that were indexed but not stored won't be in the document. This behavior
is frequently a source of confusion

Thanks
Farouk A

Search Discussions

  • Senthil at Nov 7, 2010 at 8:30 am
    Hi,
    I recommend you to try simple indexer and searcher code from book which
    clear the confusion.

    You need to specify the indexing folder and all the fields and values
    selected for indexing will stored in that folder. And during search, it
    searches from index and get the reference file path for search result too.

    regards
    Senthil

    On Sun, Nov 7, 2010 at 8:18 PM, farouk alhassan wrote:

    Hi All,

    I'm new to Lucene and have picked up the Lucene in Action book to get
    started. Really enjoying it but I have a small nagging question.

    Is the index stored in the same "physical document" as the fields and
    values? If not, where is it stored and how is it linked.

    This is because of this statement in the book

    When you retrieve a document from the index, only stored fields will be
    present. For example, fields that were indexed but not stored won't be in
    the document. This behavior
    is frequently a source of confusion

    Thanks
    Farouk A

  • Farouk alhassan at Nov 7, 2010 at 9:09 am
    Thanks for your response.
    I have already done that and understand the code perfectly.

    Just to rephrase my question

    What is the relationship between an index and a document at the conceptual level.

    Does an index include a document or an index is a collection of documents?

    Also is index == document if there is only one document?

    Thanks

    --- On Sun, 7/11/10, Senthil wrote:

    From: Senthil <senthilruban@gmail.com>
    Subject: Re: Newbie Question
    To: java-user@lucene.apache.org
    Date: Sunday, 7 November, 2010, 8:30

    Hi,
    I recommend you to try simple indexer and searcher code from book which
    clear the confusion.

    You need to specify the indexing folder and all the fields and values
    selected for indexing will stored in that folder. And during search, it
    searches from index and get the reference file path for search result too.

    regards
    Senthil

    On Sun, Nov 7, 2010 at 8:18 PM, farouk alhassan wrote:

    Hi All,

    I'm new to Lucene and have picked up the Lucene in Action book to get
    started. Really enjoying it but I have a small nagging question.

    Is the index stored in the same "physical document" as the fields and
    values? If not, where is it stored and how is it linked.

    This is because of this statement in the book

    When you retrieve a document from the index, only stored fields will be
    present. For example, fields that were indexed but not stored won't be in
    the document. This behavior
    is frequently a source of confusion

    Thanks
    Farouk A

  • Israel Tsadok at Nov 7, 2010 at 9:54 am
    (If I may)
    In Lucene terminology, an "index" is what would be a "database" in RDBMS
    terminology. It's the whole thing.
    A document is akin to a row in a table. Most of the interesting stuff in
    lucene revolves around locating the document, not retrieving the data
    actually stored inside it. This is done using Term Vectors, Norms, Term
    Frequencies, Document Frequencies etc. These are not stored per document,
    but are rather properties of the whole index, and they are therefore similar
    to the concept of "index" in an RDBMS.

    I hope I didn't make to much of a mess trying to clear things up. I probably
    missed some parts and may have misrepresented others, but this is roughly
    how I look at it.

    Israel
    On Sun, Nov 7, 2010 at 11:09 AM, farouk alhassan wrote:

    Thanks for your response.
    I have already done that and understand the code perfectly.

    Just to rephrase my question

    What is the relationship between an index and a document at the conceptual
    level.

    Does an index include a document or an index is a collection of documents?

    Also is index == document if there is only one document?

    Thanks

    --- On Sun, 7/11/10, Senthil wrote:

    From: Senthil <senthilruban@gmail.com>
    Subject: Re: Newbie Question
    To: java-user@lucene.apache.org
    Date: Sunday, 7 November, 2010, 8:30

    Hi,
    I recommend you to try simple indexer and searcher code from book which
    clear the confusion.

    You need to specify the indexing folder and all the fields and values
    selected for indexing will stored in that folder. And during search, it
    searches from index and get the reference file path for search result too.

    regards
    Senthil


    On Sun, Nov 7, 2010 at 8:18 PM, farouk alhassan <osbert252003@yahoo.com
    wrote:
    Hi All,

    I'm new to Lucene and have picked up the Lucene in Action book to get
    started. Really enjoying it but I have a small nagging question.

    Is the index stored in the same "physical document" as the fields and
    values? If not, where is it stored and how is it linked.

    This is because of this statement in the book

    When you retrieve a document from the index, only stored fields will be
    present. For example, fields that were indexed but not stored won't be in
    the document. This behavior
    is frequently a source of confusion

    Thanks
    Farouk A



  • Farouk alhassan at Nov 7, 2010 at 10:16 am
    Hi,

    Thanks for your cobntribution. very much welcomed. I like the way you relate it to a relational database. we are all familiar with databases so it makes it even much more clearer.

    I also like the indexing details ...
    Hoping to be a Lucene guru very sooon!!

    Tx

    --- On Sun, 7/11/10, Israel Tsadok wrote:

    From: Israel Tsadok <itsadok@gmail.com>
    Subject: Re: Newbie Question
    To: java-user@lucene.apache.org
    Date: Sunday, 7 November, 2010, 9:54

    (If I may)
    In Lucene terminology, an "index" is what would be a "database" in RDBMS
    terminology. It's the whole thing.
    A document is akin to a row in a table. Most of the interesting stuff in
    lucene revolves around locating the document, not retrieving the data
    actually stored inside it. This is done using Term Vectors, Norms, Term
    Frequencies, Document Frequencies etc. These are not stored per document,
    but are rather properties of the whole index, and they are therefore similar
    to the concept of "index" in an RDBMS.

    I hope I didn't make to much of a mess trying to clear things up. I probably
    missed some parts and may have misrepresented others, but this is roughly
    how I look at it.

    Israel
    On Sun, Nov 7, 2010 at 11:09 AM, farouk alhassan wrote:

    Thanks for your response.
    I have already done that and understand the code perfectly.

    Just to rephrase my question

    What is the relationship between an index and a document at the conceptual
    level.

    Does an index include a document or an index is a collection of documents?

    Also is index == document if there is only one document?

    Thanks

    --- On Sun, 7/11/10, Senthil wrote:

    From: Senthil <senthilruban@gmail.com>
    Subject: Re: Newbie Question
    To: java-user@lucene.apache.org
    Date: Sunday, 7 November, 2010, 8:30

    Hi,
    I recommend you to try simple indexer and searcher code from book which
    clear the confusion.

    You need to specify the indexing folder and all the fields and values
    selected for indexing will stored in that folder. And during search, it
    searches from index and get the reference file path for search result too.

    regards
    Senthil


    On Sun, Nov 7, 2010 at 8:18 PM, farouk alhassan <osbert252003@yahoo.com
    wrote:
    Hi All,

    I'm new to Lucene and have picked up the Lucene in Action book to get
    started. Really enjoying it but I have a small nagging question.

    Is the index stored in the same "physical document" as the fields and
    values? If not, where is it stored and how is it linked.

    This is because of this statement in the book

    When you retrieve a document from the index, only stored fields will be
    present. For example, fields that were indexed but not stored won't be in
    the document. This behavior
    is frequently a source of confusion

    Thanks
    Farouk A



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postedNov 7, '10 at 7:24a
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