Grant,
Thanks for the reply. What we're trying to do is kind of esoteric and hard to
explain without going into a lot of gory details so I was trying to keep it
simple. But I'll try to summarize.
We're trying to index entities in a relational database. One of the entities
we're trying to index is something called a Property. Think of a Property kind
of like the java.util.Properties class, i.e. a name/value pair. So some
examples of Properties might be:
State=California
City=Sacremento
ZipCode=94203
StreetName=South Main
StreetNumber=1234
Name=Joe Smith
Etc., etc.
(Note: this isn't the type of data we're storing... just trying to keep it
simple.)
Imagine that the above list represents the the set of Properties that specify
the address for a single person, Joe Smith. Each Property in the set will be
indexed by the values on the right-hand side of all the other name/value pairs
in the set, i.e.: California, Sacremento, 94203, South, Main, 1234, Joe and
Smith.
There are two types of queries that we want to do.
1) retrieve every Property matching the specified search terms, regardless of its left-hand side. For this we want to create a field in EVERY Document called "keywords" and index it by the right-hand side values as described above.
2) retrieve every Property with a given left-hand side that matches the
specified search terms. For example, find all the 'City' Properties that match
the term 'South'. For this we want to create a field with the name of the
left-hand side (e.g. State, City, ZipCode, etc.) but only in those Documents
that correspond to a Property with that left-hand side. Again this field will
be indexed by the right-hand side values as described above.
So a couple of examples from the above list might look something like:
Document: State=California
Field: 'keywords' indexed by 'California', 'Sacremento', '94203', etc.
Field: 'State' indexed by 'California', 'Sacremento', '94203', etc.
Document: City=Sacremento
Field: 'keywords' indexed by 'California', 'Sacremento', '94203', etc.
Field: 'City' indexed by 'California', 'Sacremento', '94203', etc.
Now if I'm interested in all the Properties that match the word "South", I search the index on the "keywords" field for the term "South". This will return both documents above.
But if I'm only interested in any 'City' Properties that match the term 'South' I search the index
on the "City" field for the term "South". This will only return the
'City=Sacremento' document above because it's the only Document of the two that even has a 'City'
field in it.
But in any case, the 'State' field and the 'City' field are indexed exactly the
same way as the 'keywords' field. Which is why I was wondering if there was a
way to just create these fields as copies of the 'keywords' field.
Here is a code sample where I'm creating the index. We're using Hibernate search to search the
indexes, thus the "id" and "_hibernate_class" fields.
Query q = em.createQuery("select p from Property p");
List<Property> properties = q.getResultList();
for (Property p : properties)
{
// Indexing property.
Document doc = new Document();
doc.add(new Field("id",
Integer.toString(p.getId()),
Field.Store.YES,
Field.Index.UN_TOKENIZED));
doc.add(new Field("_hibernate_class",
Property.class.getCanonicalName(),
Field.Store.YES,
Field.Index.UN_TOKENIZED));
TokenStream tokenStream = new PropertyTokenStream(p);
doc.add(new Field("keywords", tokenStream));
propertyIndexWriter.addDocument(doc);
tokenStream.close();
// Here is where I would like to add the second field that is a copy
// of the "keywords" field just created above. Note: the call
// p.getCharacteristic().getName() is getting the name of the
// left-hand side of the Property as described above.
TokenStream tokenStream = new PropertyTokenStream(p);
doc.add(new Field(p.getCharacteristic().getName(), tokenStream));
propertyIndexWriter.addDocument(doc);
tokenStream.close();
}
Hope that clears it up.
BTW, in case this seems like a strange way to index things, I will also add
that we are doing it this way in order to impose a heirarchical structure on
Properties. So my example above should really look like this:
State=California
City=Sacremento
ZipCode=94203
StreetName=South Main
StreetNumber=1234
Name=Joe Smith
Use your imagination to visualize what the tree might look like with millions of peoples' addresses. Now
imagine trying to tokenize the Document corresponding to "State=California". Each path thru the
tree from root (State) to leaf (Name) represents a set of Properties that is used to index the
"keywords" field in the "State=California" document. In other words it takes a long time
to index. This is why I'm looking for a way to just copy one field to another.
There is a lot more to our design to facilitate this hierarchical structure but
this is probably more than you wanted to know. :)
thanks in advance,
--
Bill Chesky * Sr. Software Developer * SunGard * FAME Energy * 1194 Oak Valley
Drive * Ann Arbor, MI 48103
Tel 734-332-4405 * Fax 734-332-4440 * [EMAIL PROTECTED]
www.sungard.com/energy
-----Original Message-----
From: Grant Ingersoll [mailto:[EMAIL PROTECTED]
Sent: Friday, June 27, 2008 7:26 AM
To: java-user@lucene.apache.org
Subject: Re: Can you create a Field that is a copy of another Field?
On Jun 27, 2008, at 12:01 AM, <[EMAIL PROTECTED]> <[EMAIL PROTECTED]
> wrote:
Hello Lucene Gurus,
I'm new to Lucene so sorry if this question basic or naïve.
I have a Document to which I want to add a Field named, say, "foo"
that is tokenized, indexed and unstored. I am using the
"Field(String name, TokenStream tokenStream)" constructor to create
it. The TokenStream may take a fairly long time to return all its
tokens.
Can you share some code here? What's the reasoning behind using it
(not saying it's wrong, just wondering what led you to it)? Are you
just loading it up from a file, string or something or do you have
another reason?
Now for querying reasons I want to add another Field named, say,
"bar", that is tokenized and indexed in exactly the same way as
"foo". I could just pass it the same TokenStream that I used to
create "foo" but since it takes so long to return all its tokens, I
was wondering if there is a way to say, create "bar" as a copy of
"foo". I looked thru the javadoc but didn't see anything.
By exactly the same, do you really mean exactly the same? What's the
point of that? What are the "querying reasons"?
You may want to look at the TeeTokenFilter and the SinkTokenizer, but
I guess I'd like to know more about what's going on before fully
recommending anything.
Is this possible in Lucene or do I just have to bite the bullet
build the new Field using the same TokenStream again?
--
Bill Chesky * Sr. Software Developer * SunGard * FAME Energy * 1194
Oak Valley Drive * Ann Arbor, MI 48103
Tel 734-332-4405 * Fax 734-332-4440 * [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]
www.sungard.com/energy <blocked::http://www.sungard.com/energy>
--------------------------
Grant Ingersoll
http://www.lucidimagination.com
Lucene Helpful Hints:
http://wiki.apache.org/lucene-java/BasicsOfPerformance
http://wiki.apache.org/lucene-java/LuceneFAQ
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