From: Hannes Wyss <hwyss@...>
Date: 2005-12-20T23:58:11+09:00
Subject: Re: [ANN] Object Database Access v 1.0 released

Lou 

On Tue, Dec 20, 2005 at 11:19:44PM +0900, Lou Vanek wrote:
>How would you do a search?

I'll have to eat my own example here: we've only ever been interested in
string search - i.e. find all users whose last name begins with 'Van':

<example>

require 'odba'
require 'odba/index_definition'

class User
  attr_accessor :first_name, :last_name
  include ODBA::Persistable
  def initialize(first_name, last_name)
    @first_name = first_name
    @last_name = last_name
  end
end

index_def = ODBA::IndexDefinition.new
index_def.index_name = 'users_by_last_name'
index_def.origin_klass = 'User'
index_def.target_klass = 'User'
index_def.resolve_search_term = 'last_name.downcase'

ODBA.storage.dbi = DBI.connect('DBI:pg:test', 'test', '')
ODBA.cache.create_index(index_def, Object)

composer = User.new('Ludwig', 'Van Beethoven')
composer.odba_store
painter = User.new('Vincent', 'Van Gogh')
painter.odba_store
scientist = User.new('Albert', 'Einstein')
scientist.odba_store

ODBA.cache.retrieve_from_index('users_by_last_name', 'van') 
  -> [composer, painter]

</example>

>For example, how would you find all Counters with a pos > 10 but not 13?
>Is the search done centrally, or must you download all Counters before
>you can do the search?
The numerical Counter#pos case could be done, but is not implemented..

Hannes 

-- 
Mit freundlichen Gr�ssen / best regards

Hannes Wyss
Konzeption & Entwicklung

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