SequelRuby对象映射框架

Sequel 是一个 Ruby 语言的对象映射框架（ORM），提供了线程安全、连接池以及 DSL 语言用来构造查询和表模型。

示例代码：

require "rubygems"
require "sequel"

# connect to an in-memory database
DB = Sequel.sqlite

# create an items table
DB.create_table :items do
  primary_key :id
  String :name
  Float :price
end

# create a dataset from the items table
items = DB[:items]

# populate the table
items.insert(:name => 'abc', :price => rand * 100)
items.insert(:name => 'def', :price => rand * 100)
items.insert(:name => 'ghi', :price => rand * 100)

# print out the number of records
puts "Item count: #{items.count}"

# print out the average price
puts "The average price is: #{items.avg(:price)}"