#202 Active Record Queries in Rails 3

Feb 22, 2010 | 10 minutes | Rails 3.0, Active Record

Rails 3 introduces a new query interface for performing finds in Active Record. See how it works along with the changes in named scopes.

Click to Play Video ▶

Download:
source codeProject Files in Zip (99.6 KB)
mp4Full Size H.264 Video (15.1 MB)
m4vSmaller H.264 Video (10.7 MB)
webmFull Size VP8 Video (31.6 MB)
ogvFull Size Theora Video (24 MB)

Browse Source Code

Resources

          ruby
                
        # Article.find(:all, :order => "published_at desc", :limit => 10)
Article.order("published_at desc").limit(10)

# Article.find(:all, :conditions => ["published_at <= ?", Time.now], :include => :comments)
Article.where("published_at <= ?", Time.now).includes(:comments)

# Article.find(:first, :order => "published_at desc")
Article.order("published_at").last
        
# Article.find(:all, :order => "published_at desc", :limit => 10)
Article.order("published_at desc").limit(10)

# Article.find(:all, :conditions => ["published_at <= ?", Time.now], :include => :comments)
Article.where("published_at <= ?", Time.now).includes(:comments)

# Article.find(:first, :order => "published_at desc")
Article.order("published_at").last

          rails console
                
        Article.all
articles = Article.order("name")
articles.all
articles.first
Article.recent.all
puts Article.recent.to_sql
        
Article.all
articles = Article.order("name")
articles.all
articles.first
Article.recent.all
puts Article.recent.to_sql

          articles_controller.rb
                
        @articles = Article.order("name")

if params[:hidden]
  @articles = @articles.where(:hidden => (params[:hidden] == "1"))
end
        
@articles = Article.order("name")

if params[:hidden]
  @articles = @articles.where(:hidden => (params[:hidden] == "1"))
end

          models/active_record.rb
                
        scope :visible, where("hidden != ?", true)
scope :published, lambda { where("published_at <= ?", Time.zone.now) }
scope :recent, visible.published.order("published_at desc")
        
scope :visible, where("hidden != ?", true)
scope :published, lambda { where("published_at <= ?", Time.zone.now) }
scope :recent, visible.published.order("published_at desc")