MongoDB.md

Install for Debain from here

PyMongo Tutorial (not official)

PyMongo official GitRepo

Python Mongo ODM - MongoEngine

Mongo with Python - Good Examples and doc

Understanding MongoDB

• Database
  • Collection/s
    • Document/s
• Collections do not enforce a schema
• Document has dynamic schema
• Document is a set of Key Value pair

RDBMS	MongoDB
Database	Database
Table	Collection
Row	Document
Column	Field
Table Join	Embedded Documents
Primary Key	Default key_id is given by MongoDB

Creating a Database

# if not present then created else selected
use databasename
# list current db name
db
# list all database
show dbs
# Adding a document in current db
db.movie.insert({
"name":"xyz"
})

Deleting a Database

use databasename
db.dropDatabase()

Creating a Collection

db.createCollection(name, options) # options is like a document itself, where we tell size etc
# example db.createCollection("mycollection")
# example db.createCollection("mycol", {capped:true, autoIndexId:true, size:6142800, max:10000})

showcollections # shows the created collection
# MongoDB automatically creates a collection when we add some document to a not created collection
# example: db/magicalCollection.insert({"name":"I love LP"})

Dropping a database

db.mycollection.drop()

Datatypes in MongoDB

• String
• Integer
• Boolean
• Double
• Min/Max keys
• Arrays
• Timestamp
• Object
• Null
• Symbol
• Date
• Object Id
• Binary data
• Code
• Regular expression

Inserting a document

db.collectionname.insert({"name":"Kush"}) # Inserting a single document
db.collectionname.insert([{...}, {...}, {...}]) # Inserting multiple documents

Querying Documents

db.collectionname.find() # returns everything
db.collectionname.find({"number":9588}) # returns all, and iter is returned not array
db.collectionname.find({"number":9588}).pretty() # A prettier output
db.collectionname.findOne({"number":9588}) # returns only 1

Updating, Deleting, Projection, Sorting and Limiting Documents in MongoDB

• You can use update or save

# Updating
db.mycollection.update({'title':'MongoDB Overview'}, {$set:{'title':'New MongoDB Overview'}})
db.mycollection.update({'title':'MongoDB Overview'}, {$set:{'title':'New MongoDB Overview'}}, {multi:true}) # Multiple updates#

# Deleting
db.mycollection.remove({'title':'MongoDB Overview'}) # justOne=1 to only delete one

# Projection - retrive only some of the key:value pair, which are marked as 1
db.mycol.find({}, {"title":1, _id:0}) # list all but only title

# Limiting Records
db.mycollection.find().limit(100)

# Sorting Documents - 1 for asc, -1 for dec
db.mycollection.find().sort({'likes':1}) # here likes is a key

MongoDB command GISTS

MongoDB cheatsheet