Basic operations for MongoDB in Python: connect and query instances

MongoDB is a database based on distributed file storage. Written by the C++ language. Designed to provide WEB applications with scalable, high-performance data storage solutions. It is characterized by high performance, easy to deploy, easy to use, storage of data is very convenient.

MongoDB is simple to use

Join database

In [1]: import pymongo

In [2]: from pymongo import Connection

In [3]: connection = Connection('192.168.1.3', 27017) //Create a join 

Connection related parameters

Connection([host='localhost'[, port=27017[, pool_size=None[, auto_start_request=None[, timeout=None[, slave_okay=False[, network_timeout=None[, document_class=dict[, tz_aware=True]]]]]]]]])

Database operation

In [9]: c.database_names() //Lists all database names 

Out[9]: [u'test', u'admin', u'yuhen', u'sms', u'local']
In [10]: c.server_info() //View server-related information 

Out[10]:

{u'bits': 64,

 u'gitVersion': u'nogitversion',

 u'ok': 1.0,

 u'sysInfo': u'Linux yellow 2.6.24-27-server #1 SMP Fri Mar 12 01:23:09 UTC 2010 x86_64 BOOST_LIB_VERSION=1_40',

 u'version': u'1.2.2'}
In [16]: db = c['test']　//Select database 

In [17]: db.collection_names() //Lists all collection names in the current database 

Out[17]: [u'system.indexes', u'fs.files', u'fs.chunks', u'test_gao']
In [23]: db.connection //View the join information 

Out[23]: Connection('192.168.1.3', 27017)
In [24]: db.create_collection('test_abeen') //Create a new collection 

Out[24]: Collection(Database(Connection('192.168.1.3', 27017), u'test'), u'test_abeen')
In [25]: db.last_status() //Check the last operation status 

Out[25]: {u'err': None, u'n': 0, u'ok': 1.0}
In [26]: db.name //View the current database name 

Out[26]: u'test'
In [27]: db.profiling_info() //View the configuration information 

Out[27]: []
In [28]: db.profiling_level()

Out[28]: 0.0

Set operations

In [31]: db.collection_names() //View the current database for all collection names 

Out[31]:

[u'system.indexes',

 u'fs.files',

 u'fs.chunks',

 u'test_gao',

 u'system.users',

 u'test_abeen']
In [32]: c = db.test_abeen //Select set 

In [33]: c.name //View the current collection name 

Out[33]: u'test_abeen'
In [35]: c.full_name //View the full name of the current collection 

Out[35]: u'test.test_abeen'

In [36]: c.database //View the current collection database information 

Out[36]: Database(Connection('192.168.1.3', 27017), u'test')
In [38]: post = {"author":"Mike","text":"this is a test by abeen"}

In [39]: posts = db.posts

In [40]: posts.insert(post) //Insert the document into the database collection, and by default create the collection 

Out[40]: ObjectId('4c358492421aa91e70000000')

In [41]: db.collection_names() //Displays all collection names 

Out[41]:

[u'system.indexes',

 u'fs.files',

 u'fs.chunks',

 u'test_gao',

 u'system.users',

 u'test_abeen',

 u'posts']
In [42]: posts.find_one() //Find information from the collection 

Out[42]:

{u'_id': ObjectId('4c358492421aa91e70000000'),

 u'author': u'Mike',

 u'text': u'this is a test by abeen'}

In [52]: p.update({"author":"Mike"},{"$set":{"author":"abeen","text":"this is a test by abeen shan shan"}})//Update collection document information 

In [55]: list(p.find())

Out[55]:

[{u'_id': ObjectId('4c358492421aa91e70000000'),

  u'author': u'abeen',

  u'text': u'this is a test by abeen shan shan'}]
In [96]: list(posts.find())

Out[96]:

[{u'_id': ObjectId('4c358492421aa91e70000000'),

  u'author': u'Mike',

  u'text': u'this is a test by abeen'},

 {u'_id': ObjectId('4c358ad4421aa91e70000002'), u'a': u'aa', u'b': u'bb'},

 {u'_id': ObjectId('4c358ad9421aa91e70000003'), u'a': u'aa', u'b': u'bb'},

 {u'_id': ObjectId('4c358abb421aa91e70000001'),

  u'a': u'abeen',

  u'b': u'this bb is updated'}]

In [97]: posts.remove({"a":"abeen"}) //Delete qualified documents 

In [98]: list(posts.find())

Out[98]:

[{u'_id': ObjectId('4c358492421aa91e70000000'),

  u'author': u'Mike',

  u'text': u'this is a test by abeen'},

 {u'_id': ObjectId('4c358ad4421aa91e70000002'), u'a': u'aa', u'b': u'bb'},

 {u'_id': ObjectId('4c358ad9421aa91e70000003'), u'a': u'aa', u'b': u'bb'}]
In [102]: db.collection_names()

Out[102]:

[u'system.indexes',

 u'fs.files',

 u'fs.chunks',

 u'test_gao',

 u'system.users',

 u'test_abeen',

 u'posts',

 u'doc_abeen']
In [104]: db.drop_collection("doc_abeen") //Delete the collection 

In [105]: db.collection_names()

Out[105]:

[u'system.indexes',

 u'fs.files',

 u'fs.chunks',

 u'test_gao',

 u'system.users',

 u'test_abeen',

 u'posts']

code

In [113]: result = db.posts.find({"a":"aa"})//Find the < br / >
In [114]: type(result)

Out[114]: <class 'pymongo.cursor.Cursor'>

In [119]: list(result)

Out[119]:

[{u'_id': ObjectId('4c358ad4421aa91e70000002'), u'a': u'aa', u'b': u'bb'},

 {u'_id': ObjectId('4c358ad9421aa91e70000003'), u'a': u'aa', u'b': u'bb'}]

The find format

find([spec=None[, fields=None[, skip=0[, limit=0[, timeout=True[, snapshot=False[, tailable=False[, sort=None[, max_scan=None[, as_class=None[, **kwargs]]]]]]]]]]])

code

In [120]: db.posts.count()//Current collection document number 

Out[120]: 3

In [121]: type(db.posts)

Out[121]: <class 'pymongo.collection.Collection'>
In [138]: posts.rename('test_abeen')//Rename the current collection 

In [139]: db.collection_names()

Out[139]:

[u'system.indexes',

 u'fs.files',

 u'fs.chunks',

 u'test_gao',

 u'system.users',

 u'test_abeen']
In [151]: for post in c.find({"a":"aa"}).sort("a"): //Query the side-by-side sequence 

    post

Out[152]: {u'_id': ObjectId('4c358ad4421aa91e70000002'), u'a': u'aa', u'b': u'bb'}

Out[152]: {u'_id': ObjectId('4c358ad9421aa91e70000003'), u'a': u'aa', u'b': u'bb'}

> db.foo.insert( { x : 1, y : 1 } )

> db.foo.insert( { x : 2, y : "string" } )

> db.foo.insert( { x : 3, y : null } )

> db.foo.insert( { x : 4 } )
//Query #1 y is null or does not exist 

> db.foo.find( { "y" : null } ) 

{ "_id" : ObjectId("4dc1975312c677fc83b5629f"), "x" : 3, "y" : null }

{ "_id" : ObjectId("4dc1975a12c677fc83b562a0"), "x" : 4 }
//Query #2 y is null 

> db.foo.find( { "y" : { $type : 10 } } )

{ "_id" : ObjectId("4dc1975312c677fc83b5629f"), "x" : 3, "y" : null }
//Query #3: result that y does not exist 

> db.foo.find( { "y" : { $exists : false } } )

{ "_id" : ObjectId("4dc1975a12c677fc83b562a0"), "x" : 4 }