MongoDB is a document database that provides high performance, high availability, and easy scalability. It uses a document-oriented data model where data is stored in documents that contain field and value pairs similar to JSON objects. Documents can be embedded within other documents to create complex hierarchical relationships between data. MongoDB supports replication and automatic sharding for scalability and high availability.

1. MongoDB
Ganesh Kunwar

2. Introduction
MongoDB is a document database that provides high performance, high availability, and easy
scalability.
•Document Database:
oA record in MongoDB is a document, which is a data structure composed of field and value
pairs
osimilar to JSON objects

3. Introduction
•High Performance
oEmbedding makes reads and writes fast.
oIndexes can include keys from embedded documents and arrays.
oOptional streaming writes (no acknowledgments).
•High Availability
oReplicated servers with automatic master failover.
•Easy Scalability
oAutomatic sharding distributes collection data across machines.
oEventually-consistent reads can be distributed over replicated servers.

4. Terminology
•Database:
oA physical container for collection.
oEach database gets its own set of files on the file system.
oA single MongoDB server typically has multiple databases.
•Collection:
oA grouping of MongoDB documents.
oA collection is the equivalent of an RDBMS table.
oA collection exists within a single database.
oCollections do not enforce a schema.
oDocuments within a collection can have different fields.
•Document:
oA record in a MongoDB collection and the basic unit of data in MongoDB.
oDocument is the equivalent of an RDBMS row.
oDocuments are analogous to JSON objects but exist in the database in a more type-rich format
known as BSON.

5. Terminology
•Field:
oA name-value pair in a document.
oA document has zero or more fields.
oFields are analogous to columns in relational databases.
•Embedded documents and linking:
oTable Join
•Primary Key:
oA record‟s unique immutable identifier.
oIn an RDBMS, the primary key is typically an integer stored in each row‟s id field.
oIn MongoDB, the _id field holds a document‟s primary key which is usually a BSON ObjectId.

6. Data Types
•null
oNull can be used to represent both a null value and nonexistent field.
o{“x”: null}
•boolean
oused for the values „true‟ and „false‟.
o{“x”: true}
•64-bit integer
•64-bit floating point number
o{“x” : 3.14}
•string
o{“x” : “string”}
•object id
ounique 12-byte ID for documents
o{“x”:ObjectId()}

7. Data Types
•date
oDate are stored in milliseconds since the epoch. The time zone is not stored.
o{“x”:new Date()}
•code
oDocument can also contain JavaScript code
o{“x”: function() {/*.......*/}}
•binary data
•undefined
o{“x”: undefined}
•array
o{“x”: [“a”, “b”, “c”]}
•embedded document
oDocument can contain entire documents, embedded as values in the parent document.
o{“x”: {“name” : “Your Name”}}

8. MongoDB Commands
•Start MongoDB
omongo
•List All Database
oshow databases;
•Create and use Database
ouse databas_name;
•Check current database selected
odb
•Create New collection
odb.createCollection(collectionName);
•Show All collections
oshow collections
•Drop Database
odb.dropDatabase();
•Drop Collection
odb.collection_name.drop();

9. MongoDB Query
•Insert Document
>db.collection_name.insert(document)
•Example;
>db.mycol.insert({
_id: ObjectId(7df78ad8902c),
title: 'MongoDB Overview',
description: 'MongoDB is no sql database',
by: ganesh kunwar,
url: 'http://www.ganeshkunwar.com.np',
tags: ['mongodb', 'database', 'NoSQL'],
likes: 100
})

10. MongoDB Query
•Find()
oquery data from collection
o> db.COLLECTION_NAME.find()
{ "_id" : ObjectId("53371ed996322bd29e878e2b"), "title" : "MongoDB Overview",
"description" : "MongoDB is no sql database", "by" : "ganesh kunwar", "url" :
"http://www.ganeshkunwar.com.np", "tags" : [ "mongodb", "database", "NoSQL" ], "likes" : 100 }
•Pretty()
odisplay the result in formatted way
o> db.COLLECTION_NAME.find().pretty()
{
_id: ObjectId(7df78ad8902c),
title: 'MongoDB Overview',
description: 'MongoDB is no sql database',
by: ganesh kunwar,
url: 'http://www.ganeshkunwar.com.np',
tags: ['mongodb', 'database', 'NoSQL'],
likes: 100
}

11. MongoDB Query
•findOne()
oreturns only one document.
•And in MongoDB
o> db.mycol.find(key1: value1, key2: value2)
•OR in MongoDB
o> db.mycol.find($or: [{key1: value1}, {key2, value2}] )
•And and OR together
o> db.myclo.find(key1: val1, $or: [{key2: value2}, {key3, value3}] )

13. Update
•Syntax:
o>db.COLLECTION_NAME.update(SELECTIOIN_CRITERIA, UPDATED_DATA)
•Example
o{ "_id" : ObjectId(5983548781331adf45ec5), "title":"MongoDB Overview"}
o>db.mycol.update({'title':'MongoDB Overview'}, {$set:{'title':'New MongoDB Tutorial'}})
o{ "_id" : ObjectId(5983548781331adf45ec5), "title":"New MongoDB Tutorial"}

14. Delete
•The remove() method
o>db.COLLECTION_NAME.remove(DELLETION_CRITTERIA)
•Remove only one
o>db.COLLECTION_NAME.remove(DELETION_CRITERIA,1)
•Remove All documents
o>db.mycol.remove()

15. Projection
•selecting only necessary data rather than selecting whole of the data of a document
•Syntax
o>db.COLLECTION_NAME.find({},{KEY:1})
•Example
o>db.mycol.find({},{"title":1})

16. Limiting Records
•The Limit() Method
oSyntax
o>db.COLLECTION_NAME.find().limit(NUMBER)
oExample
o>db.mycol.find({},{"title":1,_id:0}).limit(2)
•MongoDB Skip() Method
oaccepts number type argument and used to skip number of documents.
oSyntax
o>db.COLLECTION_NAME.find().limit(NUMBER).skip(NUMBER)
oExample
o>db.mycol.find({},{"title":1,_id:0}).limit(1).skip(1)

17. Sorting Records
•Ascending order
o>db.COLLECTION_NAME.find().sort({KEY:1})
•Descending order
o>db.COLLECTION_NAME.find().sort({KEY:-1})

18. MongoDB Backup
•Backup Options
oMongodump
oCopy files
oSnapshot disk
•Mongodump
omongodump --db mongodevdb --username mongodevdb --password YourSecretPwd
oDumps collections to *.bson files
oMirrors your structure
oCan be run in live or offline mode
•Mongorestore
omongorestore --dbpath /var/lib/mongo --db mongodevdb dump/mongodevdb

19. Questions
?

20. Thank You