Question

I’m building an e-commerce search and I am using Lucene.Net as my search engine. I am having trouble filtering my queries, though.

This is one of the documents I have indexed, with the following fields and values:

field: “name”, value: “Mochila MVP”

field: “manufacturer”, value: “Nike Accessories”

Now, when I run these searches I have the folowing results:

User typed query:

mochila^5 nike^2.5

Lucene translated it to:

(((name:mochil manufacturer:mochil)^5.0) ((name:nik manufacturer:nik)^2.5))

Results:

Brings the product “Mochila MVP”

User typed query:

mochila^5 AND nike^2.5

Lucene translated it to:

(+((name:mochil manufacturer:mochil)^5.0) +((name:nik manufacturer:nik)^2.5))

Results:

No results

User typed query:

mochila^5 +manufacturer:nike

Lucene translated it to:

((name:mochil)^5.0) +manufacturer:nike

Results:

No results

What I would like to know is why the second and third queries bring no results, because they seem to match the product’s name and manufacturer to me…

Any help is highly appreciated. Thanks in advance!

Answer 1

There are a lot of possible reasons why you get such [unexpected] results. Here’s what might help you in resolving this issue:

• How do you build your index?
  • analyzer matters
  • which fields are actually indexed (analyzed). I guess that ‘manufacturer’ might not be analyzed – note that your first query searches for both terms in all the fields (i.e. is acting like ‘catch all’)
• Take Luke and see what’s inside your index
• Also note that when you use ‘AND’ or ‘+’ this actually means ‘and these terms must be present in this field’ (i.e. such queries are stricter than your first one)