activerecord - Rails gem rails3-jquery-autocomplete: How do I query multiple fields

Question

I'm using the rails3-jquery-autocomplete gem found here: http://github.com/crowdint/rails3-jquery-autocomplete

The instructions are clear for how to query a single attribute of a model and I am able to make that work without a problem.

My Person model has two attributes that I would like to combine and query, however. They are first_name and last_name. I would like to combine them into a pseudo-attribute called full_name. Currently, I receive this error:

ActiveRecord::StatementInvalid (SQLite3::SQLException: no such column: full_name: SELECT     "people".* FROM       "people"  WHERE     (LOWER(full_name) LIKE 'cla%') ORDER BY  full_name ASC LIMIT 10):

There is no full_name attribute of the Person model, though I have the following method in the Person model file:

def full_name
  "#{self.first_name} #{self.last_name}"
end

How do I modify the Person model file so that calls to full_name queries the database to match a combination of first_name and last_name?

Answer 1

Your pseudo attribute works only on records already retrieved, but it has no bearing on searching for records. Probably the easiest solution is a named named scope like:

 scope :search_by_name, lambda { |q|
   (q ? where(["first_name LIKE ? or last_name LIKE ? or concat(first_name, ' ', last_name) like ?", '%'+ q + '%', '%'+ q + '%','%'+ q + '%' ])  : {})
 }

Thus, a call like:

Person.search_by_name(params[:q]) 

will return an appropriate result set. It will also return all entries if no param was passed (or more specifically, this scope will add nothing extra), making it an easy drop-in for the index action.