PyMongo for the Clueless

klrkdekira@gmail.com

http://www.python.org

http://www.mongodb.org/

● json-like (bson) document store

● full index support

● replication and high availability

● auto sharding

● querying

● fast in-place update

● map/reduce

● GridFS

SQL to Mongo Mapping

MySQL Term MongoTerm

database database

table collection

index index

row BSON document

column BSON field

join embedding and linking

primary key _id field

PyMongo

and

The romantic story of

Connection Part 1>>> import pymongo

>>> conn = pymongo.Connection()

is equivalent to

>>> conn = pymongo.Connection('localhost', 27017)

Getting the database

>>> db = conn.testdb

is equivalent to

>>> db = conn['testdb']

Basic Part 2Getting the collection

>>> collection = db.test_collection

also is equivalent to

>>> collection = db['test_collection']

Make it understood from now

Insert New Document(s)>>> dummy = db['dummy']

>>> dummy.insert({'key': 'a', 'value': 1})ObjectId('4e7c50eb059bf61d2f000000')

Multiple insert

>>> docs = [{'key':'b', 'value':2}, {'key':'c', 'value':3}]

>>> dummy.insert(docs)[ObjectId('4e7c552a059bf61d2f000002'), ObjectId('4e7c552a059bf61d2f000003')]

Find Part 1>>> dummy.find_one(){u'_id': ObjectId('4e7c50eb059bf61d2f000000'), u'key': u'a', u'value': 1}

>>> dummy.find()<pymongo.cursor.Cursor object at 0x2810ed0>

>>> for d in dummy.find(): print d{u'_id': ObjectId('4e7c50eb059bf61d2f000000'), u'key': u'a', u'value': 1}{u'_id': ObjectId('4e7c5544059bf61d2f000004'), u'key': u'b', u'value': 2}{u'_id': ObjectId('4e7c5544059bf61d2f000005'), u'key': u'c', u'value': 3}

Find Part 2>>> dummy.find_one({'key':'a'}){u'_id': ObjectId('4e7c50eb059bf61d2f000000'), u'key': u'a', u'value': 1}

Query by ObjectId

>>> from bson.objectid import ObjectId

>>> dummy.find_one({'_id':ObjectId('4e7c50eb059bf61d2f000000')}){u'_id': ObjectId('4e7c50eb059bf61d2f000000'), u'key': u'a', u'value': 1}

Same goes with find.

Update>>> dummy.update({'key':'a'}, {'value':2})

Update multiple document, destructive

>>> dummy.update({'key':'a'}, {'value':2}, multi=True)

Just to overwrite attributes

>>> dummy.update({'key':'a'}, {'$set':{'value':2}})

DeleteRemove multiple file

>>> dummy.remove({'key':'a'})

Remove by ObjectId

>>> dummy.remove({'_id':ObjectId('4e7c50eb059bf61d2f000000')})

Stored JS >>> db.system.js.add = "function (x, y) { return x + y; }"

>>> db.system.js.add(1, 2)3.0

>>> del db.system.js.add

QUESTION?