find by rails code example

Example 1: find in rails

# find first
  Person.find(:first) # returns the first object fetched by SELECT * FROM people
  Person.find(:first, :conditions => [ "user_name = ?", user_name])
  Person.find(:first, :conditions => [ "user_name = :u", { :u => user_name }])
  Person.find(:first, :order => "created_on DESC", :offset => 5)

  # find last
  Person.find(:last) # returns the last object fetched by SELECT * FROM people
  Person.find(:last, :conditions => [ "user_name = ?", user_name])
  Person.find(:last, :order => "created_on DESC", :offset => 5)

  # find all
  Person.find(:all) # returns an array of objects for all the rows fetched by SELECT * FROM people
  Person.find(:all, :conditions => [ "category IN (?)", categories], :limit => 50)
  Person.find(:all, :conditions => { :friends => ["Bob", "Steve", "Fred"] }
  Person.find(:all, :offset => 10, :limit => 10)
  Person.find(:all, :include => [ :account, :friends ])
  Person.find(:all, :group => "category")

Example 2: self.find_by_id

def self.find_by_id(id)
    sql = <<-SQL
    SELECT * FROM dogs WHERE id = ?
    SQL

    DB[:conn].execute(sql, id).map(){|row|
      self.new_from_db(row)
    }.first
  end