No sql

What is NoSQL Database Management SystemVarious Data Models

Type of NoSQL DBMSWhy NoSQL DBMS?

Beyond NoSQLBibliography

NoSQL Database

Sparsa Roychowdhury

IIEST,Shibpur

March 19, 2014

Sparsa Roychowdhury NoSQL Database




Outline

1 What is NoSQL Database Management System

2 Various Data Models

3 Type of NoSQL DBMS

4 Why NoSQL DBMS?

5 Beyond NoSQL

6 Bibliography





What is NoSQL?

NoSQL

NoSQL encompasses a wide variety of different databasetechnologies and were developed in response to a rise in the volumeof data stored about users, objects and products, the frequency inwhich this data is accessed, and performance and processing needs.Next Generation Databases mostly addressing some of the points:

1 non-relational

2 distributed

3 open-source

4 horizontally scalable





Various Data Models I

Data Model

A data model is the model through which we perceive andmanipulate our data. For people using a database, the data modeldescribes how we interact with the data in the database.

Relational Data Model

The relational model takes the information that we want to storeand divides it into tuples.

Tuple being a limited Data Structure it captures a set of valuesand can’t be nested. This gives Relational Model a space ofdevelopment.





Various Data Models II

Aggregate Model

Aggregate is a term that comes from Domain-Driven Design, anaggregate is a collection of related objects that we wish to treat asa unit, it is a unit for data manipulation and management ofconsistency.

1 Atomic property holds within an aggregate

2 Communication with data storage happens in unit ofaggregate

3 Dealing with aggregate is much more efficient in clusters

4 It is often easier for application programmers to work withaggregates





Key-Value DatabasesDocument DatabasesColumn-family storesGraph Stores

Type of NoSQL DBMS

There are mainly four types of NoSQL Database systems these are:

1 Key-value Stores

2 Document Databases

3 Wide Column Stores

4 Graph Stores






Key-Value Databases

Key-value store

A key-value store is a simple hash table, primary used when allaccess to the database is via primary key.

1 Key-value stores are the simplest NoSQL data stores to usefrom an API perspective

2 The client can either get the value, put the value or delete akey from the data store.

3 The value is just a blob that the data just stores

4 Application has the responsibility to understand what is stored

5 Have great performance and easily scaled






Example: I

There are many available key-value stores available in the marketsome of them are:

1 Riak

2 Redis

3 Memcached DB

4 Berkeley DB

5 Hamster DB (especially suited for embedded use)

6 Amazon Dynamo DB (not open source)

7 Project Voldemort (Open Source Implementation of DynamoDB)






Example: II

The basic comparison between the terminology between Oracleand Riak is given below.

Difference between the terminology of Oracle and Riak

Oracle RiakDatabase instance Riak cluster

table bucket

row key-value

rowid key






Document Databases

Document Stores

Documents are the main concept in document databases. Thedatabase stores and retrieves documents, which can be XML,JSON, BSON, and so on.

The documents stored are similar to each other but do nothave to be exactly the same.

Document databases store documents in the value parts ofthe key

Document stores can be thought as key-value stores wherethe value is examinable






Example: I

There are many available Document Databases available in themarket some of them are:

1 MongoDB

2 CouchDB

3 Terrastore

4 OrientDB

5 RavenDB






Example: II

The basic comparison between the terminology between Oracleand MongoDB is given below.

Difference between the terminology of Oracle and MongoDB

Oracle MongoDBDatabase instance MongoDB instance

Schema Database

table Collection

row Document

rowid id

Join DBref






Column-family stores

Column-family stores

Column-family stores allow you to store data with keys mapped tovalues and the values grouped into multiple column families, whereeach column family being a map of data.

Column-family databases store data in column families as rows

They have many columns associated with a row key

Column families are groups of related data that is oftenaccessed together

The basic unit of storage in Column-family databases is acolumn






Example: I

There are many available Column-family Databases available in themarket some of them are:

1 Cassandra

2 HBase

3 Hypertable

4 Amazon Simple DB






Example: II

The basic comparison between the terminology between RDBMSand Cassandra is given below.

Difference between the terminology of RDBMS and Cassandra

RDBMS CassandraDatabase instance cluster

Database Keyspace

table Column Family

row row

Column (same for all rows) Column (can be different per row)






Graph Stores

Graph Store Database

Graph databases are one style of NoSQL databases that uses adistribution model similar to relational databases but offers adifferent data model that makes it better at handling data withcomplex relationships.

Entities are also known as nodes, which have properties

Nodes are organized by relationships which allows to findinteresting patterns between the nodes

The organization of the graph lets the data to be stored onceand then interpreted in different ways based on relationships






Example: I






Example: II

There are many available graph Databases available in the marketsome of them are:

1 Neo4J

2 Infinite Graph

3 OrientDB

4 FlockDB





Schema MigrationsPolyglot PersistenceImpedance MismatchAuto Sharding

Why NoSQL DBMS?

Why NoSQL

When compared to relational databases, NoSQL databases aremore scalable and provide superior performance, and their datamodel addresses several issues that the relational model is notdesigned to address:

1 Schema Migrations

2 Polyglot Persistence

3 Impedance Mismatch

4 Auto Sharding architecture






Schema Migration

Schemaless nature

The recent trend in discussing NoSQL databases is to highlighttheir schemaless nature, it is a popular feature that allowsdevelopers to concentrate on the domain design without worryingabout schema changes.

with NoSQL databases, in some cases the schema does nothave to be thought about beforehand

The claim that NoSQL databases are entirely schemaless ismisleading

they store the data without regard to the schema the dataadheres to, that schema has to be defined by the application






Polyglot Persistence

The point of view of using different data stores in differentcircumstances is known as Polyglot Persistence

Most organization has mix of storage technologies for differentcircumstances

Using a single database engine for all of the requirementsusually leads to non- performant solutions

Storing transactional data, caching session information,traversing graph of customers and the products their friendsbought are essentially different problems






Impedance Mismatch

Impedance Mismatch

Impedance Mismatch means the difference between data modeland in memory data structures.

The impedance mismatch is a major source of frustration toapplication developers

Many people believed that it would lead to relationaldatabases being replaced with databases that replicate thein-memory data structures to disk

Object-Oriented Database failed to show the potential toreduce the gap






Auto Sharding

Auto Sharding

NoSQL databases usually support auto-sharding, meaning thatthey natively and automatically spread data across an arbitrarynumber of servers, without requiring the application to even beaware of the composition of the server pool

Because of the way they are structured, relational databasesusually scale vertically

This gets expensive quickly, places limits on scale, and createsa relatively small number of failure points for databaseinfrastructure

The solution is to scale horizontally, by adding servers insteadof concentrating more capacity in a single server.





Beyond NoSQL

NoSQL databases we have discussed here is only part of thepicture of polyglot persistence.

Recent attention to clustered environments has seen a rise ofdistributed file systems. Technologies like the Google FileSystem and Hadoop

We think of XML databases as document databases where thedocuments are stored in a data model compatible with XML

NoSQL is just one set of data storage technologies, we shouldconsider other data storage technologies whether or not theybear the NoSQL label.





Bibliography

Pramod J. Sadalage, Martin Fowler NoSQL Distilled: A BriefGuide to the Emerging World of Polyglot Persistence AddisonWesley, Massachusetts, 2013

http://www.mongodb.com/learn/nosql

http://www.wikipedia.org





Thank You!
