使用ruby操作MongoDB

MongoDB是基于文档、schema-free的、开源的数据库，可以操作JSON格式的数据和CouchDB类似。

从http://www.mongodb.org/display/DOCS/Downloads 下载MongoDB

解压 mongodb-linux-i686-1.2.4.tgz

tar xvf mongodb-linux-i686-1.2.4.tgz

mv mongodb-linux-i686-1.2.4 mongodb

 创建一个目录来保存数据

cd mongodb
mkdir -p data/db

 运行mongodb

bin/mongod -dbpath data/db

 打开mongo的shell实验一下：

fuliang@fuliang-laptop ~/mongodb $ bin/mongo
MongoDB shell version: 1.2.4
url: test
connecting to: test
type "help" for help
> use mydb
switched to db mydb
> j = { name: "mongo"}
{ "name" : "mongo" }
> t = { x : 3 }
{ "x" : 3 }
> db.things.save(j);
> db.things.save(t);
> db.things.find();
{ "_id" : ObjectId("4b8e7da14290b1eee23e62f6"), "name" : "mongo" }
{ "_id" : ObjectId("4b8e7da94290b1eee23e62f7"), "x" : 3 }
> exit
bye

 安装ruby gem：

sudo gem install mongo
sudo gem install mongo_ex

 安装mongo_ex可以提高性能。

使用ruby 尝试一下mongodb的一些功能

require 'rubygems'  # not necessary for Ruby 1.9
require 'mongo'

#make a connection
db = Mongo::Connection.new.db("mydb")
#db = Mongo::Connection.new("localhost").db("mydb")
#db = Mongo::Connection.new("localhost", 27017).db("mydb")
#list all database
m = Mongo::Connection.new # (optional host/port args)
m.database_names.each { |name| puts name }
m.database_info.each { |info| puts info.inspect}
#drop database
m.drop_database('things')
#look at collections
db.collection_names.each { |name| puts name }
coll = db.collection("testCollection")
#insert a document
doc = {"name" => "MongoDB", "type" => "database", "count" => 1,
       "info" => {"x" => 203, "y" => '102'}}
coll.insert(doc)
#find the first document
my_doc = coll.find_one()
p my_doc
#insert multiple documents
100.times { |i| coll.insert("i" => i) }
#count documents in a collection
puts coll.count()
#use cursor to get all document
coll.find().each { |row| p row }
#find documents with a query
coll.find("i" => 71).each { |row| p row }
coll.find("i" => {"$gt" => 50}).each { |row| p row }
coll.find("i" => {"$gt" => 20, "$lte" => 30}).each { |row| p row }
#query with regex
coll.find({"name" => /*.ongo.*/})
#create a index
coll.create_index("i")
# explicit "ascending"
coll.create_index([["i", ASCENDING]])

相关资源：
       MongoDB的官方主页： http://www.mongodb.org/display/DOCS/Home
       MongoDB的一个指南： http://www.mongodb.org/display/DOCS/Ruby+Tutorial
       MongoDB的一个幻灯片： http://www.fuchaoqun.com/2010/01/mongodb-in-action/       
       MongoMapper的git官网： . http://github.com/jnunemaker/mongomapper
       MongoMapper的一个例子： http://railstips.org/blog/archives/2009/06/27/mongomapper-the-rad-mongo-wrapper/