export data from SQL Server to MongoDB using Ruby and Rails

sqlserver2mongo.rb

require "rubygems"
require "active_record"
require "mongo"

include Mongo

# 声明一个 MongoDB client
@client = MongoClient.new('localhost', 27017)
# MongoDB db
@db = @client['your_mongo_dbname']
# MongoDB collection
@coll = @db['your_collection_name']

@coll.remove

# 连接 SQL Server 数据库的设置
ActiveRecord::Base.establish_connection(
  :adapter => "sqlserver",
  :host => "your_database_ipaddress",
  :database => "your_database_name",
  :username => "your_database_username",
  :password => "your_database_password"
)  

class FooBar < ActiveRecord::Base
  # 指定我们实际的表的名字
  self.table_name = "your_table_name"
end

# 使用 find_each 遍历我们的大数据量表
FooBar.find_each(:batch_size => 1000) do |foo|
	# 插入到 MongoDB 的 collection 中
  @coll.insert({'col1' => "#{foo.bar1}", "col2" => "#{foo.bar2}", "col3" => "#{foo.bar3}"});
end