Python MongoDB – Discussion

Discuss Python MongoDB ”; Previous Next Python is a general-purpose interpreted, interactive, object-oriented, and high-level programming language. It was created by Guido van Rossum during 1985-1990. Like Perl, Python source code is also available under the GNU General Public License (GPL). This tutorial gives enough understanding on Python programming language. This tutorial explains how to communicate with MongoDB database in detail, along with examples. Print Page Previous Next Advertisements ”;

Python MongoDB – Quick Guide

Python MongoDB – Quick Guide ”; Previous Next Python MongoDB – Introduction Pymongo is a python distribution which provides tools to work with MongoDB, it is the most preferred way to communicate with MongoDB database from python. Installation To install pymongo first of all make sure you have installed python3 (along with PIP) and MongoDB properly. Then execute the following command. C:WINDOWSsystem32>pip install pymongo Collecting pymongo Using cached https://files.pythonhosted.org/packages/cb/a6/b0ae3781b0ad75825e00e29dc5489b53512625e02328d73556e1ecdf12f8/pymongo-3.9.0-cp37-cp37m-win32.whl Installing collected packages: pymongo Successfully installed pymongo-3.9.0 Verification Once you have installed pymongo, open a new text document, paste the following line in it and, save it as test.py. import pymongo If you have installed pymongo properly, if you execute the test.py as shown below, you should not get any issues. D:Python_MongoDB>test.py D:Python_MongoDB> Python MongoDB – Create Database Unlike other databases, MongoDB does not provide separate command to create a database. In general, the use command is used to select/switch to the specific database. This command initially verifies whether the database we specify exists, if so, it connects to it. If the database, we specify with the use command doesn’t exist a new database will be created. Therefore, you can create a database in MongoDB using the Use command. Syntax Basic syntax of use DATABASE statement is as follows − use DATABASE_NAME Example Following command creates a database named in mydb. >use mydb switched to db mydb You can verify your creation by using the db command, this displays the current database. >db mydb Creating Database Using Python To connect to MongoDB using pymongo, you need to import and create a MongoClient, then you can directly access the database you need to create in attribute passion. Example Following example creates a database in MangoDB. from pymongo import MongoClient #Creating a pymongo client client = MongoClient(”localhost”, 27017) #Getting the database instance db = client[”mydb”] print(“Database created……..”) #Verification print(“List of databases after creating new one”) print(client.list_database_names()) Output Database created…….. List of databases after creating new one: [”admin”, ”config”, ”local”, ”mydb”] You can also specify the port and host names while creating a MongoClient and can access the databases in dictionary style. Example from pymongo import MongoClient #Creating a pymongo client client = MongoClient(”localhost”, 27017) #Getting the database instance db = client[”mydb”] print(“Database created……..”) Output Database created…….. Python MongoDB – Create Collection A collection in MongoDB holds a set of documents, it is analogous to a table in relational databases. You can create a collection using the createCollection() method. This method accepts a String value representing the name of the collection to be created and an options (optional) parameter. Using this you can specify the following − The size of the collection. The max number of documents allowed in the capped collection. Whether the collection we create should be capped collection (fixed size collection). Whether the collection we create should be auto-indexed. Syntax Following is the syntax to create a collection in MongoDB. db.createCollection(“CollectionName”) Example Following method creates a collection named ExampleCollection. > use mydb switched to db mydb > db.createCollection(“ExampleCollection”) { “ok” : 1 } > Similarly, following is a query that creates a collection using the options of the createCollection() method. >db.createCollection(“mycol”, { capped : true, autoIndexId : true, size : 6142800, max : 10000 } ) { “ok” : 1 } > Creating a Collection Using Python Following python example connects to a database in MongoDB (mydb) and, creates a collection in it. Example from pymongo import MongoClient #Creating a pymongo client client = MongoClient(”localhost”, 27017) #Getting the database instance db = client[”mydb”] #Creating a collection collection = db[”example”] print(“Collection created……..”) Output Collection created…….. Python MongoDB – Insert Document You can store documents into MongoDB using the insert() method. This method accepts a JSON document as a parameter. Syntax Following is the syntax of the insert method. >db.COLLECTION_NAME.insert(DOCUMENT_NAME) Example > use mydb switched to db mydb > db.createCollection(“sample”) { “ok” : 1 } > doc1 = {“name”: “Ram”, “age”: “26”, “city”: “Hyderabad”} { “name” : “Ram”, “age” : “26”, “city” : “Hyderabad” } > db.sample.insert(doc1) WriteResult({ “nInserted” : 1 }) > Similarly, you can also insert multiple documents using the insert() method. > use testDB switched to db testDB > db.createCollection(“sample”) { “ok” : 1 } > data = [ {“_id”: “1001”, “name”: “Ram”, “age”: “26”, “city”: “Hyderabad”}, {“_id”: “1002”, “name” : “Rahim”, “age” : 27, “city” : “Bangalore” }, {“_id”: “1003”, “name” : “Robert”, “age” : 28, “city” : “Mumbai” } ] [ {“_id” : “1001”, “name” : “Ram”, “age” : “26”, “city” : “Hyderabad”}, {“_id” : “1002”, “name” : “Rahim”, “age” : 27, “city” : “Bangalore”}, {“_id” : “1003”, “name” : “Robert”, “age” : 28, “city” : “Mumbai”} ] > db.sample.insert(data) BulkWriteResult({ “writeErrors” : [ ], “writeConcernErrors” : [ ], “nInserted” : 3, “nUpserted” : 0, “nMatched” : 0, “nModified” : 0, “nRemoved” : 0, “upserted” : [ ] }) > Creating a Collection Using Python Pymongo provides a method named insert_one() to insert a document in MangoDB. To this method, we need to pass the document in dictionary format. Example Following example inserts a document in the collection named example. from pymongo import MongoClient #Creating a pymongo client client = MongoClient(”localhost”, 27017) #Getting the database instance db = client[”mydb”] #Creating a collection coll = db[”example”] #Inserting document into a collection doc1 = {“name”: “Ram”, “age”: “26”, “city”: “Hyderabad”} coll.insert_one(doc1) print(coll.find_one()) Output {”_id”: ObjectId(”5d63ad6ce043e2a93885858b”), ”name”:

Python MongoDB – Update

Python MongoDB – Update ”; Previous Next You can update the contents of an existing documents using the update() method or save() method. The update method modifies the existing document whereas the save method replaces the existing document with the new one. Syntax Following is the syntax of the update() and save() methods of MangoDB − >db.COLLECTION_NAME.update(SELECTION_CRITERIA, UPDATED_DATA) Or, db.COLLECTION_NAME.save({_id:ObjectId(),NEW_DATA}) Example Assume we have created a collection in a database and inserted 3 records in it as shown below − > use testdatabase switched to db testdatabase > data = [ … {“_id”: “1001”, “name”: “Ram”, “age”: “26”, “city”: “Hyderabad”}, … {“_id”: “1002”, “name” : “Rahim”, “age” : 27, “city” : “Bangalore” }, … {“_id”: “1003”, “name” : “Robert”, “age” : 28, “city” : “Mumbai” } ] [ {“_id” : “1001”, “name” : “Ram”, “age” : “26”, “city” : “Hyderabad”}, {“_id” : “1002”, “name” : “Rahim”, “age” : 27, “city” : “Bangalore”}, {“_id” : “1003”, “name” : “Robert”, “age” : 28, “city” : “Mumbai”} ] > db.createCollection(“sample”) { “ok” : 1 } > db.sample.insert(data) Following method updates the city value of the document with id 1002. >db.sample.update({“_id”:”1002″},{“$set”:{“city”:”Visakhapatnam”}}) WriteResult({ “nMatched” : 1, “nUpserted” : 0, “nModified” : 1 }) > db.sample.find() { “_id” : “1001”, “name” : “Ram”, “age” : “26”, “city” : “Hyderabad” } { “_id” : “1002”, “name” : “Rahim”, “age” : 27, “city” : “Visakhapatnam” } { “_id” : “1003”, “name” : “Robert”, “age” : 28, “city” : “Mumbai” } Similarly you can replace the document with new data by saving it with same id using the save() method. > db.sample.save({ “_id” : “1001”, “name” : “Ram”, “age” : “26”, “city” : “Vijayawada” }) WriteResult({ “nMatched” : 1, “nUpserted” : 0, “nModified” : 1 }) > db.sample.find() { “_id” : “1001”, “name” : “Ram”, “age” : “26”, “city” : “Vijayawada” } { “_id” : “1002”, “name” : “Rahim”, “age” : 27, “city” : “Visakhapatnam” } { “_id” : “1003”, “name” : “Robert”, “age” : 28, “city” : “Mumbai” } Updating documents using python Similar to find_one() method which retrieves single document, the update_one() method of pymongo updates a single document. This method accepts a query specifying which document to update and the update operation. Example Following python example updates the location value of a document in a collection. from pymongo import MongoClient #Creating a pymongo client client = MongoClient(”localhost”, 27017) #Getting the database instance db = client[”myDB”] #Creating a collection coll = db[”example”] #Inserting document into a collection data = [ {“_id”: “101”, “name”: “Ram”, “age”: “26”, “city”: “Hyderabad”}, {“_id”: “102”, “name”: “Rahim”, “age”: “27”, “city”: “Bangalore”}, {“_id”: “103”, “name”: “Robert”, “age”: “28”, “city”: “Mumbai”} ] res = coll.insert_many(data) print(“Data inserted ……”) #Retrieving all the records using the find() method print(“Documents in the collection: “) for doc1 in coll.find(): print(doc1) coll.update_one({“_id”:”102″},{“$set”:{“city”:”Visakhapatnam”}}) #Retrieving all the records using the find() method print(“Documents in the collection after update operation: “) for doc2 in coll.find(): print(doc2) Output Data inserted …… Documents in the collection: {”_id”: ”101”, ”name”: ”Ram”, ”age”: ”26”, ”city”: ”Hyderabad”} {”_id”: ”102”, ”name”: ”Rahim”, ”age”: ”27”, ”city”: ”Bangalore”} {”_id”: ”103”, ”name”: ”Robert”, ”age”: ”28”, ”city”: ”Mumbai”} Documents in the collection after update operation: {”_id”: ”101”, ”name”: ”Ram”, ”age”: ”26”, ”city”: ”Hyderabad”} {”_id”: ”102”, ”name”: ”Rahim”, ”age”: ”27”, ”city”: ”Visakhapatnam”} {”_id”: ”103”, ”name”: ”Robert”, ”age”: ”28”, ”city”: ”Mumbai”} Similarly, the update_many() method of pymongo updates all the documents that satisfies the specified condition. Example Following example updates the location value in all the documents in a collection (empty condition) − from pymongo import MongoClient #Creating a pymongo client client = MongoClient(”localhost”, 27017) #Getting the database instance db = client[”myDB”] #Creating a collection coll = db[”example”] #Inserting document into a collection data = [ {“_id”: “101”, “name”: “Ram”, “age”: “26”, “city”: “Hyderabad”}, {“_id”: “102”, “name”: “Rahim”, “age”: “27”, “city”: “Bangalore”}, {“_id”: “103”, “name”: “Robert”, “age”: “28”, “city”: “Mumbai”} ] res = coll.insert_many(data) print(“Data inserted ……”) #Retrieving all the records using the find() method print(“Documents in the collection: “) for doc1 in coll.find(): print(doc1) coll.update_many({},{“$set”:{“city”:”Visakhapatnam”}}) #Retrieving all the records using the find() method print(“Documents in the collection after update operation: “) for doc2 in coll.find(): print(doc2) Output Data inserted …… Documents in the collection: {”_id”: ”101”, ”name”: ”Ram”, ”age”: ”26”, ”city”: ”Hyderabad”} {”_id”: ”102”, ”name”: ”Rahim”, ”age”: ”27”, ”city”: ”Bangalore”} {”_id”: ”103”, ”name”: ”Robert”, ”age”: ”28”, ”city”: ”Mumbai”} Documents in the collection after update operation: {”_id”: ”101”, ”name”: ”Ram”, ”age”: ”26”, ”city”: ”Visakhapatnam”} {”_id”: ”102”, ”name”: ”Rahim”, ”age”: ”27”, ”city”: ”Visakhapatnam”} {”_id”: ”103”, ”name”: ”Robert”, ”age”: ”28”, ”city”: ”Visakhapatnam”} Print Page Previous Next Advertisements ”;

Python MongoDB – Sort

Python MongoDB – Sort ”; Previous Next While retrieving the contents of a collection, you can sort and arrange them in ascending or descending orders using the sort() method. To this method, you can pass the field(s) and the sorting order which is 1 or -1. Where, 1 is for ascending order and -1 is descending order. Syntax Following is the syntax of the sort() method. >db.COLLECTION_NAME.find().sort({KEY:1}) Example Assume we have created a collection and inserted 5 documents into it as shown below − > use testDB switched to db testDB > db.createCollection(“myColl”) { “ok” : 1 } > data = [ … {“_id”: “1001”, “name”: “Ram”, “age”: “26”, “city”: “Hyderabad”}, … {“_id”: “1002”, “name”: “Rahim”, “age”: 27, “city”: “Bangalore”}, … {“_id”: “1003”, “name”: “Robert”, “age”: 28, “city”: “Mumbai”}, … {“_id”: “1004”, “name”: “Romeo”, “age”: 25, “city”: “Pune”}, … {“_id”: “1005”, “name”: “Sarmista”, “age”: 23, “city”: “Delhi”}, … {“_id”: “1006”, “name”: “Rasajna”, “age”: 26, “city”: “Chennai”} ] > db.sample.insert(data) BulkWriteResult({ “writeErrors” : [ ], “writeConcernErrors” : [ ], “nInserted” : 6, “nUpserted” : 0, “nMatched” : 0, “nModified” : 0, “nRemoved” : 0, “upserted” : [ ] }) Following line retrieves all the documents of the collection which are sorted in ascending order based on age. > db.sample.find().sort({age:1}) { “_id” : “1005”, “name” : “Sarmista”, “age” : 23, “city” : “Delhi” } { “_id” : “1004”, “name” : “Romeo”, “age” : 25, “city” : “Pune” } { “_id” : “1006”, “name” : “Rasajna”, “age” : 26, “city” : “Chennai” } { “_id” : “1002”, “name” : “Rahim”, “age” : 27, “city” : “Bangalore” } { “_id” : “1003”, “name” : “Robert”, “age” : 28, “city” : “Mumbai” } { “_id” : “1001”, “name” : “Ram”, “age” : “26”, “city” : “Hyderabad” } Sorting the Documents Using Python To sort the results of a query in ascending or, descending order pymongo provides the sort() method. To this method, pass a number value representing the number of documents you need in the result. By default, this method sorts the documents in ascending order based on the specified field. If you need to sort in descending order pass -1 along with the field name − coll.find().sort(“age”,-1) Example Following example retrieves all the documents of a collection arranged according to the age values in ascending order − from pymongo import MongoClient #Creating a pymongo client client = MongoClient(”localhost”, 27017) #Getting the database instance db = client[”b_mydb”] #Creating a collection coll = db[”myColl”] #Inserting document into a collection data = [ {“_id”: “1001”, “name”: “Ram”, “age”: “26”, “city”: “Hyderabad”}, {“_id”: “1002”, “name”: “Rahim”, “age”: “27”, “city”: “Bangalore”}, {“_id”: “1003”, “name”: “Robert”, “age”: “28”, “city”: “Mumbai”}, {“_id”: “1004”, “name”: “Romeo”, “age”: 25, “city”: “Pune”}, {“_id”: “1005”, “name”: “Sarmista”, “age”: 23, “city”: “Delhi”}, {“_id”: “1006”, “name”: “Rasajna”, “age”: 26, “city”: “Chennai”} ] res = coll.insert_many(data) print(“Data inserted ……”) #Retrieving first 3 documents using the find() and limit() methods print(“List of documents (sorted in ascending order based on age): “) for doc1 in coll.find().sort(“age”): print(doc1) Output Data inserted …… List of documents (sorted in ascending order based on age): {”_id”: ”1005”, ”name”: ”Sarmista”, ”age”: 23, ”city”: ”Delhi”} {”_id”: ”1004”, ”name”: ”Romeo”, ”age”: 25, ”city”: ”Pune”} {”_id”: ”1006”, ”name”: ”Rasajna”, ”age”: 26, ”city”: ”Chennai”} {”_id”: ”1001”, ”name”: ”Ram”, ”age”: ”26”, ”city”: ”Hyderabad”} {”_id”: ”1002”, ”name”: ”Rahim”, ”age”: ”27”, ”city”: ”Bangalore”} {”_id”: ”1003”, ”name”: ”Robert”, ”age”: ”28”, ”city”: ”Mumbai”} Print Page Previous Next Advertisements ”;

Python MongoDB – Find

Python MongoDB – Find ”; Previous Next You can read/retrieve stored documents from MongoDB using the find() method. This method retrieves and displays all the documents in MongoDB in a non-structured way. Syntax Following is the syntax of the find() method. >db.COLLECTION_NAME.find() Example Assume we have inserted 3 documents into a database named testDB in a collection named sample using the following queries − > use testDB > db.createCollection(“sample”) > data = [ {“_id”: “1001”, “name”: “Ram”, “age”: “26”, “city”: “Hyderabad”}, {“_id”: “1002”, “name” : “Rahim”, “age” : 27, “city” : “Bangalore” }, {“_id”: “1003”, “name” : “Robert”, “age” : 28, “city” : “Mumbai” } ] > db.sample.insert(data) You can retrieve the inserted documents using the find() method as − > use testDB switched to db testDB > db.sample.find() { “_id” : “1001”, “name” : “Ram”, “age” : “26”, “city” : “Hyderabad” } { “_id” : “1002”, “name” : “Rahim”, “age” : 27, “city” : “Bangalore” } { “_id” : “1003”, “name” : “Robert”, “age” : 28, “city” : “Mumbai” } > You can also retrieve first document in the collection using the findOne() method as − > db.sample.findOne() { “_id” : “1001”, “name” : “Ram”, “age” : “26”, “city” : “Hyderabad” } Retrieving Data (find) Using Python The find_One() method of pymongo is used to retrieve a single document based on your query, in case of no matches this method returns nothing and if you doesn’t use any query it returns the first document of the collection. This method comes handy whenever you need to retrieve only one document of a result or, if you are sure that your query returns only one document. Example Following python example retrieve first document of a collection − from pymongo import MongoClient #Creating a pymongo client client = MongoClient(”localhost”, 27017) #Getting the database instance db = client[”mydatabase”] #Creating a collection coll = db[”example”] #Inserting document into a collection data = [ {“_id”: “101”, “name”: “Ram”, “age”: “26”, “city”: “Hyderabad”}, {“_id”: “102”, “name”: “Rahim”, “age”: “27”, “city”: “Bangalore”}, {“_id”: “103”, “name”: “Robert”, “age”: “28”, “city”: “Mumbai”} ] res = coll.insert_many(data) print(“Data inserted ……”) print(res.inserted_ids) #Retrieving the first record using the find_one() method print(“First record of the collection: “) print(coll.find_one()) #Retrieving a record with is 103 using the find_one() method print(“Record whose id is 103: “) print(coll.find_one({“_id”: “103”})) Output Data inserted …… [”101”, ”102”, ”103”] First record of the collection: {”_id”: ”101”, ”name”: ”Ram”, ”age”: ”26”, ”city”: ”Hyderabad”} Record whose id is 103: {”_id”: ”103”, ”name”: ”Robert”, ”age”: ”28”, ”city”: ”Mumbai”} To get multiple documents in a single query (single call od find method), you can use the find() method of the pymongo. If haven’t passed any query, this returns all the documents of a collection and, if you have passed a query to this method, it returns all the matched documents. Example #Getting the database instance db = client[”myDB”] #Creating a collection coll = db[”example”] #Inserting document into a collection data = [ {“_id”: “101”, “name”: “Ram”, “age”: “26”, “city”: “Hyderabad”}, {“_id”: “102”, “name”: “Rahim”, “age”: “27”, “city”: “Bangalore”}, {“_id”: “103”, “name”: “Robert”, “age”: “28”, “city”: “Mumbai”} ] res = coll.insert_many(data) print(“Data inserted ……”) #Retrieving all the records using the find() method print(“Records of the collection: “) for doc1 in coll.find(): print(doc1) #Retrieving records with age greater than 26 using the find() method print(“Record whose age is more than 26: “) for doc2 in coll.find({“age”:{“$gt”:”26″}}): print(doc2) Output Data inserted …… Records of the collection: {”_id”: ”101”, ”name”: ”Ram”, ”age”: ”26”, ”city”: ”Hyderabad”} {”_id”: ”102”, ”name”: ”Rahim”, ”age”: ”27”, ”city”: ”Bangalore”} {”_id”: ”103”, ”name”: ”Robert”, ”age”: ”28”, ”city”: ”Mumbai”} Record whose age is more than 26: {”_id”: ”102”, ”name”: ”Rahim”, ”age”: ”27”, ”city”: ”Bangalore”} {”_id”: ”103”, ”name”: ”Robert”, ”age”: ”28”, ”city”: ”Mumbai”} Print Page Previous Next Advertisements ”;