NOSQL AND MONGO DB

Haritha K

What is NoSQL ?

NoSQL

NoSQL

Types of NoSQL

Philosophy of NoSQL

“One size fits all” no longer applies

“Non relational” DBs are more scalable, especially horizontally

Focus on speed, performance, flexibility, scalability

Not concerned with transactional stuff and relational semantics

DBs should be on-demand commodity, in a cloud like fashion.

Examples of NoSQL

CAP theorem

Statement: One can only have two of Consistency, Availability, and tolerance to network Partitions at the same time.

Consistency (all nodes see the same data at the same time)

Availability (a guarantee that every request receives a response about whether it was successful or failed)

Partition tolerance (the system continues to operate despite arbitrary message loss or failure of part of the system)

CAP theorem

Mongo DB

How popular is MongoDB?

MONGO DB

Humongous ( Huge + monstrous )

A document model NoSQL DB

Has all advantages of NoSQL

Data modeling matches application objects

Fits better with object oriented programming

Schema-free,fast and scalable

Developed and supported by 10gen.First release – Feb 2009,latest – Aug 2014.

How data is stored?

How data is stored?

How data is stored?

BSON – Binary JSON

Documents are stored in BSON format

BSON is a binary serialization of JSON like objects

This is extremely powerful as Mongo understands JSON natively

Any valid JSON can be easily imported and queried.

Schema-less and flexible.

Terminology

SQL Terms/Concepts MongoDB Terms/Concepts

database database

table collection

row document or BSON document

column Field

index Index

table joins embedded documents and linking

primary key primary key

Specify any unique column or column combination as

primary key.

Holds a document’s primary key which is usually a BSON

object

Data Modification – Insert

Data modifictions refers to operations that create,update or delete data

In MongoDB, these operations modify the data of a single collection.

For the update and delete operations, criteria can be specified.

Update and Save

The db.collection.update() method can accept query criteria to determine which documents to update as well as an option to update multiple rows.

Format : db.COLLECTION_NAME.update(SELECTIOIN_CRITERIA,

UPDATED_DATA)

db.inventory.update( { name:“jack"}, {$inc:{age:-1}}, {multi:true})

The db.collection.save() method can replace an existing document.

Format : db.COLLECTION_NAME.save({_id:ObjectId(),NEW_DATA})

db.inventory.save( {_id: ObjectId("540451f745fa71ef2dd18c85"),"empId" : 3333,

“dept" : "sales"} )

Read

Read operations or queries will retrieve the data stored in the database.

Queries selects documents from a single collection.

The db.collection.find() method accepts query criteria and projections and returns a cursor to the matching documents.

Format : db.collection.find(<criteria>, <projection>)

db.inventory.find({},{KEY:1})

db.inventory.find({name:"a"},{age:true})

db.inventory.find( {tags:"machine"}) db.inventory.find( {tags:"machine"}).limit(1)

db.inventory.findOne().tags

Remove

Remove method to remove documents from a collection.

Format: db.COLLECTION_NAME.remove(DELLETION_CRITTERIA)

Can remove all documents from a collection

db.inventory.remove()

Remove all documents matching a condition.

db.inventory.remove( {test:"ok"} )

Limit the operation to remove just a single document.

db.inventory.remove( {test:"ok"},1 )

Replication

Replication & Read Preferences

Sharding

Sharding & Distributed Queries

Write Concerns

Stronger settings: slower, better guarantee

Errors Ignored

Acknowledged

Unacknowledged

Journaled

Replica Acknowledged

Write Concerns

Disadvantages of NoSQL

No common standards. Each database does things differently.

Querying data does not involve familiar SQL model to find records.

NoSQL databases are relatively immature and constantly evolving.

Because a NoSQL database avoids ACID (Atomicity, Consistency, Isolation, Durability) model, there is no guarantee that all of the data will be success

Thank You………..