Counting the number of fields

Imagine a situation where we have a simple document to be indexed to Solr with titles and tags. What we will want to do is separate the premium documents that have more tag values because they are better in terms of our business. Of course, we can count the number of tags ourselves, but why not let Solr do this? This recipe will show you how to do this with Solr.

How to do it...

Let's look at the steps we need to take to count the number of field values.

1. We start with the index structure. What we need to do is put the following section in the schema.xml file:

   <field name="id" type="string" indexed="true" stored="true" required="true" />
   <field name="title" type="text_general" indexed="true" stored="true"/>
   <field name="tags" type="string" indexed="true" stored="true" multiValued="true"/>
   <field name...