You can also go further and ask:
Give me all the people that drive a toyota (company->car->people):
*q=*:*&fq=*:* AND _query_:"{!join to=id from=ownerId}id:* AND
_query_:{!join to=companyId from=id}name:toyo*"*
If we divide this query in fragments we got:
- *q=*:** which is restriction over people, so you can add here every
constraint you can imagine about people.
In the other side fq can be divided in two parts:
- *id:* AND _query_:{!join to=companyId from=id}name:toyo** which
extracts all the cars that satisfy nothing ("id:*") and which companiId
points to a company with a name that starts with "toyo" (AND _query_:{!join
to=companyId from=id}name:toyo*)
- *{!join to=id from=ownerId}* Use the former list of cars to make a
join with the documents pointed by ownedId (i.e. people).
Regards.
On Wed, Nov 6, 2013 at 9:43 PM, Alvaro Cabrerizo <topor...@gmail.com> wrote:
> For example, a dummy schema (if we index the former data in separate
> documents) should look like this:
>
> ...
> <field name="color" type="string" indexed="true"
> stored="true" />
> <field name="year" type="int" indexed="true" stored="true"
> />
> <field name="companyId" type="string" indexed="true"
> stored="true" />
> <field name="ownerId" type="string" indexed="true"
> stored="true" />
> <field name="name" type="text" indexed="true"
> stored="true" />
> <field name="numEmployees" type="int" indexed="true"
> stored="true" />
> <field name="established" type="int" indexed="true"
> stored="true" />
> <field name="age" type="text" indexed="true"
> stored="true" />
> <field name="profession" type="text" indexed="true"
> stored="true" />
> <field name="spouseId" type="string" indexed="true"
> stored="true" />
> <field name="carOwnedId" type="string" indexed="true"
> stored="true" />
> ...
>
> So as you can see the schema.xml has no information about foreign keys.
>
> With this schema we can answer:
>
> - Give me all the cars done by toyota:
>
> q=id:*&fq={!join%20to=companyId%20from=id}id:23
>
> q=id:*&fq={!join%20to=companyId%20from=id}name:toyo*%20AND%20id:2*
>
> As you can imagine q gives me all the documents and later I filter them
> saying just to return those which companyId has a company tha
> t satisfies id=23 or in the second example its name start by toyo and its
> id starts by 2.
>
> Regards.
>
>
> On Wed, Nov 6, 2013 at 7:55 PM, Alvaro Cabrerizo <topor...@gmail.com>wrote:
>
>> You can check these links:
>>
>> http://wiki.apache.org/solr/Join
>>
>>
>> http://stackoverflow.com/questions/12665797/is-solr-4-0-capable-of-using-join-for-multiple-core
>>
>> Regards.
>>
>>
>> On Wed, Nov 6, 2013 at 1:00 AM, Tech Id <tech.login....@gmail.com> wrote:
>>
>>> Hi Alvaro,
>>>
>>> Could you please point me to some link from where I can see how to index
>>> two documents separately (joined by foreign keys).
>>> Or if you can oblige by putting down some details here itself.
>>>
>>> *For example*, say if user has entities like :
>>> car {id:5, color:red, year:2004, companyId:23, ownerId: 57},
>>> company {id:23, name: toyota, numEmployees:1000, established:1980},
>>> owner {id: 57, name: John, age: 50, profession: doctor, spouseId: 78,
>>> carOwnedId: 5},
>>> owner {id: 78, name: Maria, age: 45, profession: doctor, spouseId: 57,
>>> carOwnedId: 55}
>>> etc.
>>> 1) How can the above entities be put into Solr with their foreign keys?
>>> 2) Do we need to flatten them absolutely?
>>> 3) How are cyclic joins handled in flattening?
>>>
>>> Some good link on how a join query can be actually run would also be
>>> appreciated.
>>> (I have some links on the reading part, but a complete example would be
>>> good).
>>>
>>> Thanks
>>>
>>>
>>>
>>> On Tue, Nov 5, 2013 at 10:53 AM, Alvaro Cabrerizo <topor...@gmail.com
>>> >wrote:
>>>
>>> > In my case, everytime I've used joins, the FROM field was a multivalued
>>> > string and the TO was an univalued string.
>>> >
>>> > Regards.
>>> > El 05/11/2013 18:37, "Tech Id" <tech.login....@gmail.com> escribió:
>>> >
>>> > > I think Solr has the ability to do joins in the latest version as
>>> > verified
>>> > > on this issue: https://issues.apache.org/jira/browse/SOLR-3076
>>> > >
>>> > > And some online resources point to this example:
>>> > >
>>> > >
>>> >
>>> http://blog.mikemccandless.com/2012/01/searching-relational-content-with.html
>>> > > However, I am not sure if the above example is a complete one.
>>> > > It leaves a lot for a fresh solr-user to guess about how to
>>> customize the
>>> > > schema and how to index two documents into Solr before doing a join.
>>> > >
>>> > >
>>> > >
>>> > > On Tue, Nov 5, 2013 at 9:31 AM, Tech Id <tech.login....@gmail.com>
>>> > wrote:
>>> > >
>>> > > > Hi,
>>> > > >
>>> > > > I have been searching for an example of joins using solr/lucene.
>>> > > > But I have not found anything either on the net or in the
>>> src/examples.
>>> > > >
>>> > > > Can someone please point me to the same?
>>> > > > Ideally, I need a join working with Solrj APIs (Please let me know
>>> if
>>> > > this
>>> > > > group is Lucene-specific).
>>> > > >
>>> > > >
>>> > > > Best Regards
>>> > > >
>>> > > >
>>> > >
>>> >
>>>
>>
>>
>
