Use Python 2.7 CURD for non-relational database MongoDB

During database operations, some data formats are irrelevant, that is, when it is non-relational, we will use non-relational databases,

MongoDB is a distributed non-relational database written by C ++. Its Applications are mature, stable, and API operations are simple. Currently, it supports Python 2.7 and does not support Python 3. x package.

Here are some examples of using Python 2.7 to operate MongoDB:

1. Access Local 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 ("cocould 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

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

# Reference to the Database object for the lifetime of your program shocould

# Be sufficient.

Assert dbh. connection = c

Print "Successfully set up a database handle"

If _ name _ = "_ main __":

Main ()

 

 

2. insert operation:

'''

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 ("cocould 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. Update operations

'''

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 update operation

# 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 ("cocould not connect to MongoDB: % s" % e)

Sys. exit (1)

If _ name _ = "_ main __":

Main ()

4. delete operation.

'''

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 such ENTs are matched.

# Print "Number of deleted record rows: \ t" % count

Except ConnectionFailure, e:

Sys. stderr. write ("cocould not connect to MongoDB: % s" % e)

Sys. exit (1)

If _ name _ = "_ main __":

Main ()

These examples are written in the MongoDB & Python bookbox.