Ein paar Notizen zu Python und MongoDB 🙂 MongoDB ist eine NoSQL Datenbank, weitere Infos -> Wikipedia 🙂
Aktuelle MongoDB Version installieren (auf Ubuntu 16.04)
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 2930ADAE8CAF5059EE73BB4B58712A2291FA4AD5
echo "deb [ arch=amd64,arm64 ] https://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.6 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.6.list
apt install apt-transport-https
apt update
apt-get install -y mongodb-org
siehe auch: https://docs.mongodb.com/manual/tutorial/install-mongodb-on-ubuntu/
Python Erweiterung pymongo für MongoDB installieren mit pip
python -m pip install pymongo
siehe auch: https://api.mongodb.com/python/current/
Verbindung zur MongoDB
from pymongo import MongoClient
client = MongoClient('localhost', 27017)
Connect zur Datenbank test
db = client.test
Collection myCollection in Datenbank test verbinden
coll = db.myCollection
Einen Datensatz anlegen in einer Collection
post = {"author":"Fritz Fuchs", "book":"Hasenjagd"}
>>> coll.insert_one(post)
<pymongo.results.InsertOneResult object at 0x7fd0136ce3f8>
Mehrere Datensätze in einer Collection anlegen
>>> posts = [{"author":"Fritz Fuchs", "book":"Hasenjagd 5"}, {"author":"Fritz Fuchs", "book":"Hasenjagd 6"}, {"author":"Fritz Fuchs", "book":"Hasenjagd 7"}]
>>> result = coll.insert_many(posts)
>>> result.inserted_ids
[ObjectId('5b259b2c39d9c04f7b43af01'), ObjectId('5b259b2c39d9c04f7b43af02'), ObjectId('5b259b2c39d9c04f7b43af03')]
Datensatz suchen
>>> coll.find_one({"author":"Fritz Fuchs"})
{u'_id': ObjectId('5b25998139d9c04f7b43aefe'), u'book': u'Hasenjagd', u'author': u'Fritz Fuchs'}
Datensatz mit Regex suchen
>>> coll.find_one({"author":{"$regex": "^Fritz.*"}})
{u'_id': ObjectId('5b25998139d9c04f7b43aefe'), u'book': u'Hasenjagd', u'author': u'Fritz Fuchs'}
Datensatz mit ObjectId abrufen
>>> from bson.objectid import ObjectId
>>> coll.find_one({"_id":ObjectId("5b25998139d9c04f7b43aefe")})
{u'_id': ObjectId('5b25998139d9c04f7b43aefe'), u'book': u'Hasenjagd', u'author': u'Fritz Fuchs'}
Mehrere Datensätze abrufen z.B. mit Regex
>>> for post in coll.find({"author":{"$regex": "^Fritz.*"}}):
... print post
...
{u'_id': ObjectId('5b25998139d9c04f7b43aefe'), u'book': u'Hasenjagd', u'author': u'Fritz Fuchs'}
{u'_id': ObjectId('5b259a8939d9c04f7b43aeff'), u'book': u'Hasenjagd 2', u'author': u'Fritz Fuchs'}
{u'_id': ObjectId('5b259a9039d9c04f7b43af00'), u'book': u'Hasenjagd 3', u'author': u'Fritz Fuchs'}
Index erzeugen für Collection z.B. Username ist Unique
>>> import pymongo
>>> db.users.create_index([('user_id', pymongo.ASCENDING)], unique=True)
u'user_id_1'
>>> new_users = [{'user_id':'max'},{'user_id':'fritz'}]
>>> db.users.insert_many(new_users)
<pymongo.results.InsertManyResult object at 0x7fd0136cee18>
>>> new_user = {'user_id':'max'}
>>> db.users.insert_one(new_user)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python2.7/dist-packages/pymongo/collection.py", line 683, in insert_one
session=session),
File "/usr/local/lib/python2.7/dist-packages/pymongo/collection.py", line 599, in _insert
bypass_doc_val, session)
File "/usr/local/lib/python2.7/dist-packages/pymongo/collection.py", line 580, in _insert_one
_check_write_command_response(result)
File "/usr/local/lib/python2.7/dist-packages/pymongo/helpers.py", line 207, in _check_write_command_response
_raise_last_write_error(write_errors)
File "/usr/local/lib/python2.7/dist-packages/pymongo/helpers.py", line 188, in _raise_last_write_error
raise DuplicateKeyError(error.get("errmsg"), 11000, error)
pymongo.errors.DuplicateKeyError: E11000 duplicate key error collection: test.users index: user_id_1 dup key: { : "max" }
ObjectId als String
>>> new_user = {'user_id':'maxx'}
>>> result = db.users.insert_one(new_user)
>>> result
<pymongo.results.InsertOneResult object at 0x7fd0122410e0>
>>> result.inserted_id
ObjectId('5b259ead39d9c04f7b43af07')
>>> str(result.inserted_id)
'5b259ead39d9c04f7b43af07'
String ObjectId zu ObjectId Object wandeln und für Suche verwenden
>>> from bson.objectid import ObjectId
>>> str_obj = '5b259ead39d9c04f7b43af07'
>>> users.find_one({'_id':ObjectId(str_obj)})
{u'_id': ObjectId('5b259ead39d9c04f7b43af07'), u'user_id': u'maxx'}
Datensatz löschen
>>> users.delete_one({'_id':ObjectId(str_obj)})
<pymongo.results.DeleteResult object at 0x7fd0136cee18>
Datensatz aktualisieren
>>> new_user = {'user_id':'maxx', 'name':'Hans Wurst'}
>>> users.insert_one(new_user)
>>> change = {'name': 'Fritz Fritz'}
>>> users.update_one({'_id':ObjectId('5b25a14f39d9c04f7b43af08')}, {'$set':change} )
<pymongo.results.UpdateResult object at 0x7fd0136ced40>
>>> users.find_one({'_id':ObjectId('5b25a14f39d9c04f7b43af08')})
{u'_id': ObjectId('5b25a14f39d9c04f7b43af08'), u'user_id': u'maxx', u'name': u'Fritz Fritz'}
Bereich bei Suche
>>> client = MongoClient()
>>> db = client.huu
>>> c = db.test
>>> posts = [{"author":"Fritz Fuchs", "book":"Hasenjagd 5", "boo":1}, {"author":"Fritz Fuchs", "book":"Hasenjagd 6", "boo":5}, {"author":"Fritz Fuchs", "book":"Hasenjagd 7", "boo":10}]
>>> c.insert_many(posts)
>>> for post in c.find({"boo": {"$lt": 6}}).sort("author"):
... print post
...
{u'author': u'Fritz Fuchs', u'_id': ObjectId('5b25bb9539d9c05186997b54'), u'book': u'Hasenjagd 5', u'boo': 1}
{u'author': u'Fritz Fuchs', u'_id': ObjectId('5b25bb9539d9c05186997b55'), u'book': u'Hasenjagd 6', u'boo': 5}
>>> for post in c.find({"boo": {"$gt": 6}}).sort("author"):
... print post
...
{u'author': u'Fritz Fuchs', u'_id': ObjectId('5b25bb9539d9c05186997b56'), u'book': u'Hasenjagd 7', u'boo': 10}
>>> for post in c.find({"boo": {"$lt": 6, "$gt": 3}}).sort("author"):
... print post
...
{u'author': u'Fritz Fuchs', u'_id': ObjectId('5b25bb9539d9c05186997b55'), u'book': u'Hasenjagd 6', u'boo': 5}
Quelle / weitere Beispiele: http://api.mongodb.com/python/current/tutorial.html
