How to blacklist/demote search results with certain set of keywords in ElasticSearch and Apache Solr?

Question

I was comparing both ElasticSearch and Apache Solr for a search solution. Data that will go into the system is not moderated and I don't want anyone to search for something and some sexually explicit content to flash on the very top of the search result. But I don't want to remove them for search results either. I want to demote them, so that they come later in the search results. Can I do this in Solr or ElasticSearch ? Some pointers towards how to achieve this will be helpful.

Answer 1

In Solr you can't give "negative boosts" per se but you can boost everything that doesn't have the term. This can be done with the boost query:

...&bq=(*:* -erotic)^999

or in solrconfig.xml:

<str name="bq">(*:* -erotic)^999</str>

Where "erotic" is the term to which you wish to give a "negative boost". To add another term, add another bq=....