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():