using_update_and_set.py

from pymongo import MongoClient
import sys
import datetime

client = MongoClient('localhost', 27017)

db = client.school
scores = db.score	

def removeDate():
	print "\nremove all date\n"
	query = {}
	try:
		scores.update({}, {'$unset': {'review_date': 1}}, multi=True)
	except:
		print "Unexpected error", sys.exc_info()[0] 
	

def using_save():
	print "command save"
	query = {'student_id': 1, 'type': 'exam'}
	try:
		score = scores.find_one(query)
		print "before", score
		score['review_date'] = datetime.datetime.utcnow()
		scores.save(score)
		score = scores.find_one(query)
		print "after", score
	except:
		print "Unexpected error", sys.exc_info()[0] 
		raise

def using_update():
	print "command update"
	query = {'student_id': 1, 'type': 'exam'}
	try:
		score = scores.find_one(query)
		print "before", score
		score['review_date'] = datetime.datetime.utcnow()

		#sovrascrive l'intero documento
		scores.update(query, score) 

		score = scores.find_one(query)
		print "after", score
	except:
		print "Unexpected error", sys.exc_info()[0] 
		raise

def using_set():
	print "command set"
	query = {'student_id': 1, 'type': 'exam'}
	try:
		score = scores.find_one(query)
		print "before", score

#		piu efficiente perche setta solo il campo desiderato senza sovrascrive gli altri
		scores.update(query, {'$set': {'review_date': datetime.datetime.utcnow()}}) 
		score = scores.find_one(query)
		print "after", score
	except:
		print "Unexpected error", sys.exc_info()[0] 
		raise



removeDate()
using_save()
removeDate()
using_update()
removeDate()
using_set()