# Indexed Search Engine & Boolean Search

**URL:** <https://www.ruby-forum.com/t/indexed-search-engine-boolean-search/54626>\
**Category:** Engines\
**Created:** [March 10, 2006, 1:32pm UTC](https://www.ruby-forum.com/t/indexed-search-engine-boolean-search/54626 "2006-03-10T13:32:44Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![piers](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/b3f665/32.png) [@piers](https://www.ruby-forum.com/u/piers)\
**Post date:** [March 10, 2006, 1:32pm UTC](https://www.ruby-forum.com/t/indexed-search-engine-boolean-search/54626/1 "2006-03-10T13:32:44Z")

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Hi  
I’ve got the Indexed Search engine up and running, but it currently  
returns results for all items matching any of the terms in the search  
field.

I was wondering if anyone knew whether there’s a switch I’m missing so  
that it returns all items matching every terms in the search field?

I’ve been playing around with the IndexableRecord.rb code (l.100 on):

# Search the index. Phrase is expected to be a string of

# one or more words. The phrase will be tokenized with Tokenizer,

# stop words will be removed, and each term will be stemmed.

# This will allow a search for “Running” to return records with

# the terms “run”, “ran” and “runner”

def IndexableRecord.search(phrase)  
results = []  
terms = Tokenizer.tokenize(phrase).collect do |t| t.stem end  
terms.empty? ? [] : Context.find(:all, :include =\> :terms,  
:conditions =\> [“term IN (?)”, terms])  
end

but am getting in a complete spin trying to sort out the conditions for  
a boolean and, partly because MySQL doesn’t seem to support intersects.

Any help/suggestions/ideas would be hugely appreciated!

Piers

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<div class="post-metadata">

**Author:** ![piers](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/b3f665/32.png) [@piers](https://www.ruby-forum.com/u/piers)\
**Post date:** [March 10, 2006, 6:58pm UTC](https://www.ruby-forum.com/t/indexed-search-engine-boolean-search/54626/2 "2006-03-10T18:58:56Z")

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Hi Piers

I’ve given this some thought, and I’m not sure of the best way to  
achieve it  
at the moment without intersection support. I had been kind of  
procrastinating doing something like this until there was some demand -  
and  
you are the first person to request it. 😉

A very basic (and not very efficient) implementation would be to iterate  
over the terms storing the results in an array and using ruby’s  
intersection  
operator (&) to find the set of matches for all terms.

I’ll noodle on this a bit - and if you have other ideas, please feel  
free to  
email or post them.

Thanks  
Lance

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<div class="post-metadata">

**Author:** ![piers](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/b3f665/32.png) [@piers](https://www.ruby-forum.com/u/piers)\
**Post date:** [March 11, 2006, 5:56pm UTC](https://www.ruby-forum.com/t/indexed-search-engine-boolean-search/54626/3 "2006-03-11T17:56:12Z")

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Lance,

> A very basic (and not very efficient) implementation would be to iterate  
> over the terms storing the results in an array and using ruby’s  
> intersection operator (&) to find the set of matches for all terms.

If you can see past the novice coding, then the following seems to work.  
As you say though, there are almost certainly more graceful ways of  
doing it.

def IndexableRecord.search(phrase)  
results = []  
terms = Tokenizer.tokenize(phrase).collect do |t| t.stem end  
#terms.empty? ? [] : Context.find(:all, :include =\> :terms,  
# :conditions =\> [“term IN (?)”, terms])

```
if terms.empty?
  return results
else
  first_term = true
  holder =[]
  terms.each do |t|
    @query = "Select contexts.id from contexts, contexts_terms, 

```

terms where  
terms.term = ‘#{t}’ and terms.id =  
contexts\_terms.term\_id and  
contexts\_terms.context\_id = contexts.id"

```
    if first_term
      first_results = Context.find_by_sql(@query)
      first_term = false
      holder = first_results
    else
      next_results = Context.find_by_sql(@query)
      holder = holder & next_results
    end
    if holder.empty?
      return results
    end
  end

  holder.each do |h|
    results << Context.find(h.id)
  end
  return results
end

```

end

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<div class="post-metadata">

**Author:** ![piers](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/b3f665/32.png) [@piers](https://www.ruby-forum.com/u/piers)\
**Post date:** [March 13, 2006, 5:26am UTC](https://www.ruby-forum.com/t/indexed-search-engine-boolean-search/54626/4 "2006-03-13T05:26:46Z")

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Hi Piers

I’ve made modifications to the code so that you may now supply a :type  
option to the search  
method, as in IndexableRecord::search(“foo bar”, :type =\> :all). The  
:type  
can option can be either :any or :all with the default being :any. When  
set  
to :any, results containing any of the terms in the search phrase are  
returned. When set to :all results containing all of the terms in the  
search  
phrase are returned.

This is in version 0.2.1

The implementation for the :all option looks like this:

```
results = Context.find(:all, :include => :terms,
                       :conditions => ["term = ?", terms.shift])
terms.each do |term|
  results = results & Context.find(:all, :include => :terms,
                          :conditions => ["term = ?", term])
end

```

Not as efficient as I’d like, but OK I suppose.

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<div class="post-metadata">

**Author:** ![piers](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/b3f665/32.png) [@piers](https://www.ruby-forum.com/u/piers)\
**Post date:** [March 13, 2006, 1:20pm UTC](https://www.ruby-forum.com/t/indexed-search-engine-boolean-search/54626/5 "2006-03-13T13:20:52Z")

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Thanks Lance

> Not as efficient as I’d like, but OK I suppose.

Blindingly much better than my effort 🙂

Piers