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ReplSetConnection.new(['db1.app.com'], ['db2.app.com'],
  :rs_name => "myapp")

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# To compile from the root of the c driver
scons
gcc -static -std=c99 -Wall query.c -I./src -L. -lbson -lmongoc -o query

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require 'rubygems'
require 'mongoid'

Mongoid.configure do |config|
  config.master = Mongo::Connection.new.db("mongoid")
end

class Event
       include Mongoid::Document
       include Mongoid::Timestamps

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#include "bson.h"
#include "mongo.h"
#include <stdio.h>

void main() {
  bson b;
  bson_buffer bb;

  bson_buffer_init( &bb );
  bson_append_string( &bb, "uid", "123456789");

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// Compile this as follows:
// javac -classpath mongo.jar:bson.jar:. Perf.java
// Then run it like this:
// time java -classpath mongo.jar:bson.jar:. Perf

import com.mongodb.Mongo;
import com.mongodb.DBCollection;
import com.mongodb.BasicDBObject;
import com.mongodb.BasicDBList;
import com.mongodb.DBObject;

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MongoDB Aggregation

Min and Max
db.posts.find({}).sort({x: 1}).limit(1)  return the post with the smallest value for x
db.posts.find({}).sort({x: -1}).limit(1) return the post with the largest value for x
Note: min and max queries are most efficient with an index on the field being sorted on.

Count
db.posts.count(selector) count the number of posts matching the given selector
db.posts.count({}) count the total number of posts

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MongoDB Aggregation

Min and Max
db.posts.find({}).sort({x: 1}).limit(1)  return the post with the smallest value for x
db.posts.find({}).sort({x: -1}).limit(1) return the post with the largest value for x
Note: min and max queries are most efficient with an index on the field being sorted on.

Count
db.posts.count(selector) count the number of posts matching the given selector
db.posts.count({}) count the total number of posts

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# with multiple collections + commands for renaming back the collections

require 'mongo'

# Stop writing to your database.
# Then, for each collection:
# Specify the DB and COLLECTION you want to convert.
# Will insert all modified documents into a new collection
# called 'new_' + old_collection_name.
# Then you can delete the old collection and rename the new one

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class Hash

def prepare(start=nil)
  h = {}
  self.keys.each do |key|
    key_name = start ? "#{start}.#{key}" : key
    if self[key].is_a?(Hash)
      h.merge!(self[key].prepare(key_name))
    else
      h[key_name] = self[key]

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require 'rubygems' 
require 'rack' 
require 'mongo' 
require 'logger' 
$connection = Mongo::Connection.new( "genesis.mongohq.com", 27017, :pool_size => 
                10, :timeout => 2, :logger => Logger.new( "mongo_rack.log" ) ) 
                $db = $connection.db( "test" ) 
                $db.authenticate('user', 'password')
                $db['fs.files'].remove
                $db['fs.chunks'].remove