使用Python 2.7 CURD 操作非关系型数据库MongoDB

在进行数据库的操作过程中，有些数据的格式没有关系，也即它是非关系型的时候，我们会用到非关系型数据库，

而MongoDB是一个由C++写的分布式非关系型数据库，目前应用比较成熟，稳定，API操作比较简单，目前支持Python 2.7，还没有支持Python 3.x的包。

以下是我使用Python 2.7操作MongoDB的一些例子：

1.访问本地MongoDB

'''

Created on 2011-11-30

@author: LONMID

'''

import sys

from pymongo import Connection

from pymongo.errors import ConnectionFailure

def main():

try:

c = Connection(host="localhost", port=27017)

except ConnectionFailure, e:

sys.stderr.write("Could not connect to MongoDB: %s" % e)

sys.exit(1)

# Get a Database handle to a database named "mydb"

dbh = c["mydb"]

dbh

# Demonstrate the db.connection property to retrieve a reference to the

# Connection object should it go out of scope. In most cases, keeping a

# reference to the Database object for the lifetime of your program should

# be sufficient.

assert dbh.connection == c

print "Successfully set up a database handle"

if __name__ == "__main__":

main()

2.插入操作:

'''

Created on 2011-11-30

@author: LONMID

'''

""" An example of how to insert a document """

import sys

from datetime import datetime

from pymongo import Connection

from pymongo.errors import ConnectionFailure

def main():

try:

c = Connection(host="localhost", port=27017)

except ConnectionFailure, e:

sys.stderr.write("Could not connect to MongoDB: %s" % e)

sys.exit(1)

dbh = c["mydb"]

assert dbh.connection == c

user_doc = {

"username" : "janedoe",

"firstname" : "Jane",

"surname" : "Doe",

"dateofbirth" : datetime(1974, 4, 12),

"email" : "janedoe74@example.com",

"score" : 0

}

dbh.users.insert(user_doc, safe=True)

print "Successfully inserted document: %s" % user_doc

if __name__ == "__main__":

main()

3.更新操作

'''

Created on 2011-11-29

@author: LONMID

'''

import sys

from pymongo import Connection

from pymongo.errors import ConnectionFailure

import copy

def main():

try:

conn = Connection(host="localhost", port=27017)

print ("Connected Localhost successfully!!!!!")

dbh = conn["mydb"]

assert dbh.connection == conn

users = dbh.users.find_one({"username" : "janedoe"})

if not users:

print "no document found for username janedoe"

# else:

# for user in users:

# print user.get("username")

else:

for user in dbh.users.find(snapshot=True):

print user.get("username")

for user in dbh.users.find(snapshot=True):

print user.get("email"), user.get("score", 0)

old_user_doc = dbh.users.find_one({"username":"janedoe"})

new_user_doc = copy.deepcopy(old_user_doc)

# modify the copy to change the email address

new_user_doc["email"] = "janedoe74@example2.com"

# run the update query 更新操作

# replace the matched document with the contents of new_user_doc

dbh.users.update({"username":"janedoe"}, new_user_doc, safe=True)

except ConnectionFailure, e:

sys.stderr.write("Could not connect to MongoDB: %s" % e)

sys.exit(1)

if __name__ == "__main__":

main()

4.删除操作.

'''

Created on 2011-11-29

@author: LONMID

'''

import sys

from pymongo import Connection

from pymongo.errors import ConnectionFailure

import copy

def main():

try:

conn = Connection(host="localhost", port=27017)

print ("Connected Localhost successfully!!!!!")

dbh = conn["mydb"]

assert dbh.connection == conn

users = dbh.users.find_one({"username" : "janedoe"})

if not users:

print "no document found for username janedoe"

# else:

# for user in users:

# print user.get("username")

else:

for user in dbh.users.find(snapshot=True):

print user.get("username")

for user in dbh.users.find(snapshot=True):

print user.get("email"), user.get("score", 0)

# Delete all documents in user collection with score 1

dbh.users.remove({"score":1}, safe=True)

# remove() will not raise any exception or error if no documents are matched.

# print "删除记录行的个数:\t"%count

except ConnectionFailure, e:

sys.stderr.write("Could not connect to MongoDB: %s" % e)

sys.exit(1)

if __name__ == "__main__":

main()

这些例子是参照 MongoDB & Python书箱写成的。

学习链接：

http://api.mongodb.org/python/2.0.1/tutorial.html