That depends a bit on your database, but it is tricky and might not be
performant.
If you are more of a Java developer, you might prefer retrieving
mutliple rows per SOLR document from your dataSource (join on your
category and main table), and aggregate them in your custom
EntityProcessor. I got a far(!) better performance retrieving everything
in one query and doing the aggregation in Java. But this is, of course,
depending on your table structure and data.
Noble Paul helped me with the custom EntityProcessor, and it turned out
quite easy. Have a look at the thread with the heading from this mailing
list (SOLR-USER):
DataImportHandler / Import from DB : one data set comes in multiple rows
Cheers,
Chantal
Joel Nylund schrieb:
thanks, but im confused how I can aggregate across rows, I dont know
of any easy way to get my db to return one row for all the categories
(given the hint from your other email), I have split the category
query into a separate entity, but its returning multiple rows, how do
I combine multiple rows into 1 index entity?
thanks
Joel
On Oct 29, 2009, at 8:58 PM, Avlesh Singh wrote:
In the database this is modeled a a 1-N where category table has the
mapping of feed to category
I need to be able to query , give me all the feeds in any given
category.
How can I best model this in solr?
Seems like multiValued field might help, but how would I populate
it, and
would the query above work?.
Yes you are right. A multivalued field for "categories" is the answer.
For populating in the index -
1. If you use DIH to populate your indexes and your datasource is a
database then you can use DIH's RegexTransformer on an aggregated
list of
categories. e.g. if your database query retruns "a,b,c,d" in a
column called
"db_categories", this is how you would put it in DIH's data-config
file -
<field column="db_categories" name="categories" splityBy="," />.
2. If you "add" documents to Solr yourself multiple values for
the field
can be specified as an array or list of values in the
SolrInputDocument.
A multivalued field provides the same faceting and searching
capabilites
like regular fields. There is no special syntax.
Cheers
Avlesh
On Fri, Oct 30, 2009 at 4:55 AM, Joel Nylund <jnyl...@yahoo.com>
wrote:
Hi,
I have one index so far which contains feeds. I have been able to
de-normalize several tables and map this data onto the feed entity.
There is
one tricky problem that I need help on.
Feeds have 1 - many categories.
So Lets say we have Category1, Category2 and Category3
Feed 1 - is in Category 1
Feed 2 is in category2 and category3
Feed 3 is in category2
Feed 4 has no category
In the database this is modeled a a 1-N where category table has the
mapping of feed to category
I need to be able to query , give me all the feeds in any given
category.
How can I best model this in solr?
Seems like multiValued field might help, but how would I populate
it, and
would the query above work?.
thanks
Joel
