I have found some information to accomplish this in mongoDB, but I need it with mongoid. So I can do something like:
User.last(7000).each do ....
I'm using:
MongoDB shell version: 2.4.3
Mongoid 2.6.0
Thanks!
Now I found a solution from mongoid origin:
User.all.desc('_id').limit(7000)
It sorts the users in descending order according to the id.
Aggregations can directly be chained to a Model in rails irrespective of the ORM used. We don't need to use all. You could just do the following
User.limit(3000).desc('_id')
This will only return the Mongoid criteria. To see the data you can chain .all to the criteria. You can directly do operations on the criteria also, without having to chain .all or to_a.
Related
Is it possible to use Xpath or Xquery to query XML type fields in a database using Eloquent ORM ? I find in inconvenient to parse the XML every time and filter my results in memory. I would rather return my results from a query, is there a way to achieve that using Eloquent or I'm stuck with raw database statements?
Thank you
I reviewed the options for selecting items in Eloquent and there is not much good options to select based on XML values as you expect. You can use some wildcards and run calculations on Eloquent to filter needed data but none of these are very efficient.
We're running Solr 3.6 and are trying to apply a conditional sort on the result set. To clarify, the data is a set of bids, and we want to add the option to sort by the current user's bid, so it can't function as a regular sort (as the bid will be different for each user that runs the query).
The documents in the result set include a "CurrentUserId" and "CurrentBid" field, so I think we need something like the following to sort:
sort=((CurrentUserId = 12345) ? CurrentBid : 0) desc
This is just pseudocode, but the idea is that if the currentUserId in Solr matches the user Id (12345 in this example), then sort by CurrentBid, otherwise, just use 0.
It seems like doing a sort by query might be the way to go with achieving this (or at least form part of the solution), using something like the following query:
http://localhost:8080/solr/select/?q=:&sort=query(CurrentUserId:10330 AND CurrentBid:[1 TO *])+desc
This doesn't seem to be working for me though, and results in the following error:
sort param could not be parsed as a query, and is not a field that exists in the index: ...
The Solr documentation indicates that the query function can be used as a sort parameter from Solr 1.4 onwards, so this seems like it should work.
Any advice on how to go about achieving this would be greatly appreciated.
According to the Solr Documentation link you provided,
Any type of subquery is supported through either parameter dereferencing $otherparam or direct specification of the query string in the LocalParams via "v".
So based on the examples and your query, I think one or both of the following should work:
http://localhost:8080/solr/select/?q=:&sort=query($qq)+desc&qq=(CurrentUserId:10330 AND CurrentBid:[1 TO *])
http://localhost:8080/solr/select/?q=:&sort=query({v='CurrentUserId:10330 AND CurrentBid:[1 TO *]'})+desc
I have a mongo collection which has documents with two fields "fieldA" and "fieldB", which are timestamps and I need to get all the documents which are "(fieldB-fieldA)/6000 > 2"... So I was looking for some function in order to do this...
I saw in some posts the function "$subtract" but that seems is in mongo 2.1.x and currently I'm using 2.0.x (it's the stable), any idea how to do this with 2.0.x? or Do I need to create a new field? or Can I only do it in the application side?
btw, I'm using the ruby mongo driver...
You can use the $where operator to specify query expressions as Javascript. In the shell:
db.myCollection.find( { $where: "(this.fieldB - this.fieldA)/6000 > 2" } );
You should note, however, that Javascript execution can be very slow. If this is a one time query, $where may be an ok solution. Otherwise, storing the result of the equation in a separate field is the best way to ensure that queries are timely.
Additional information on the $where operator:
http://www.mongodb.org/display/DOCS/Advanced+Queries#AdvancedQueries-JavascriptExpressionsand%7B%7B%24where%7D%7D
I'm trying to get results of a facet query using solrj, but it seems it doesn't matter whether I add the facet query or not. I get the same document list anyway.
So this query returns the same document list...
query.setQuery(searchString);
query.setFacet(true);
query.addFacetField("CATNAME_STR");
query.addFacetQuery("CATNAME_STR:" + facetName);
...with this query
query.setQuery(searchString);
query.setFacet(true);
query.addFacetField("CATNAME_STR");
Only difference is I can get number of documents that matches the facet query with response.getFacetQuery();
I was expecting it to work like
http://localhost:8983/solr/select/?q=*%3A*&version=2.2&start=0&rows=10&indent=on&facet=on&facet.field=CATNAME_STR&fq=CATNAME_STR:Erasmus
Any ideas?
Thanks.
By the way I'm using Solr Version 3.1.0 and solr-core-3.1.0
As it turns out fq=CATNAME_STR:Erasmus does not mean query.addFacetQuery("CATNAME_STR:Erasmus") but instead query.addFilterQuery("CATNAME_STR:Erasmus")
I need to facet inside n documents which are selected like
... ORDER BY something DESC LIMIT 100
Is that possible with Solr? How?
this is a total hack, but here goes...
do your initial query, and get your results back.
construct a new query, like so:
http://localhost:8080/solr/select/?q=id%3A123+OR+id%3A456...(keep OR-ing them up)...&facet=true&facet.field=something
where you concatenate all of your ids to a new query using OR. then, when you facet on your field, the facet summary will only apply to the results.
AFAIK no, that's not supported / implemented. Facets aren't really meant to be "stats" but a guidance to the end-user. Picture yourself browsing a faceted interface and seeing facets change whenever you change sort order or paging. Faceted browsing would be useless if it worked like that.
I think this would be a nice feature for the StatsComponent though.
I think this is possible with results grouping (now in trunk!):
http://wiki.apache.org/solr/FieldCollapsing
... the only problem is that you can set only one 'facet.field' (i.e. group.field)
But the great thing is that you get scored facets!