SlideShare a Scribd company logo
SCHEMA
BY ANITA DIGGI
COURSE:-MCA 3rd
College – Srinath University, Adityapur Jamshedpur
WHAT IS SCHEMA ?
Schema is a logical description of the entire database.
It includes the name and description of records of all record types including
all associated data-Items and aggregates.
Much like a database, a data warehouse also requires to maintain a schema.
A database uses relational model, while a data warehouse uses Star,
Snowflake, and Fact Constellation schema.
TYPES OF SCHEMA
Star Schema Snowflake Schema Fact Constellations
STAR SCHEMA
Each dimension in a star schema is represented with only one-dimension
table.
A star schema is the elementary form of a dimensional model, in which
data are organized into facts and dimensions.
There is a fact table at the center. It contains the keys to each of four
dimensions.
A dimension includes reference data about the fact, such as date, item, or
customer.
The fact table in a star schema contains the measures or metrics.
The dimensional table contain the set of attributes.
ADVANTAGES OF STAR SCHEMA
Easy for users to understand
Queries use very simple joins while retrieving the data and thereby
query performance is increased.
It is simple to retrieve data for reporting, at any point of time for any
period.
DISADVANTAGE OF STAR SCHEMA
Uses large disk space
It can become complex if there are too many dimensions, attributes, rows,
or columns in the fact table.
Data redundancy is more
STAR SCHEMA DIAGRAM
SNOWFLAKE SCHEMA
Represented by centralized fact tables which are connected to multiple
dimensions tables.
Some dimension tables in the snowflake schema are normalized.
A snowflake schema is equivalent to the star schema.
A schema is known as a snowflake if one or more dimension table do not
connect directly to the fact table but must join through other dimension tables.
ADVANTAGE OF SNOWFLAKE
SCHEMA
Reduces the problem of data integrity
Uses small disk space
Improvement in query performance
Easy to understand
It is easy to update (or) maintain the Snow Flaking tables.
DISADVANTAGE OF SNOWFLAKE
SCHEMA
Adds complexity to source query joins
Snowflake schemas can have slower data access and queries.
SNOWFLAKE SCHEMA DIAGRAM
FACT CONSTELLATION SCHEMA
A fact constellation means two or more fact table sharing one or more
dimension.
It is a combination of other two schema.
A fact constellation has Multiple Fact Table, it is also known as Galaxy
Schema.
ADVANTAGE OF FACT CONSTELLATION
SCHEMA
Fact constellation schema can integrate data from multiple sources.
It is improved data retrival.
DISADVANTAGE OF fact constellation
SCHEMA
Difficult to maintain
More complex than star schema and snowflake schemas
FACT CONSTELLATION SCHEMA
diagram
THANK YOU

More Related Content

Similar to Schema in Data Mining and Data warehousing (20)

PPTX
Data warehouse 21 snowflake schema
Vaibhav Khanna
 
PDF
Difference between snowflake schema and fact constellation
Asim Saif
 
PPTX
CSC612 THIRD LECTURE ON DATA WAREHOUSE.pptx
MrNdlela
 
PPTX
Module 1.2: Data Warehousing Fundamentals.pptx
NiramayKolalle
 
DOC
Dw concepts
Krishna Prasad
 
PPTX
Data warehouse and Data Mining (PEC-IT602B).pptx
UtsavChakraborty6
 
PPTX
Data warehouse and Data Mining (PEC-IT602B).pptx
UtsavChakraborty6
 
DOC
Basics+of+Datawarehousing
theextraaedge
 
PPT
Dimensional modelling-mod-3
Malik Alig
 
PDF
Data Warehouse Basics
Ram Kedem
 
DOCX
Data modelling interview question
Sandeep Sharma IIMK Smart City,IoT,Bigdata,Cloud,BI,DW
 
PPTX
Data modeling dimensions
Dr. Dipti Patil
 
PPTX
Data modeling dimensions for dta warehousing
Dr. Dipti Patil
 
PPTX
MULTIMEDIA MODELING
Jasbeer Chauhan
 
PPTX
DataModelingTechniques.pptx
SriniRao31
 
DOCX
Star schema
Chandanapriya Sathavalli
 
PDF
(Lecture 3) Star Schema.pdf
MobeenMasoudi
 
DOCX
OracleFIT5195-2-Star Schema.pdfWeek 2 – Star SchemaSe.docx
vannagoforth
 
DOCX
OracleFIT5195-2-Star Schema.pdfWeek 2 – Star SchemaSe.docx
amit657720
 
PPTX
Enhanced_Role_of_Schemas_in_Data_Warehouse.pptx
Hardik781481
 
Data warehouse 21 snowflake schema
Vaibhav Khanna
 
Difference between snowflake schema and fact constellation
Asim Saif
 
CSC612 THIRD LECTURE ON DATA WAREHOUSE.pptx
MrNdlela
 
Module 1.2: Data Warehousing Fundamentals.pptx
NiramayKolalle
 
Dw concepts
Krishna Prasad
 
Data warehouse and Data Mining (PEC-IT602B).pptx
UtsavChakraborty6
 
Data warehouse and Data Mining (PEC-IT602B).pptx
UtsavChakraborty6
 
Basics+of+Datawarehousing
theextraaedge
 
Dimensional modelling-mod-3
Malik Alig
 
Data Warehouse Basics
Ram Kedem
 
Data modeling dimensions
Dr. Dipti Patil
 
Data modeling dimensions for dta warehousing
Dr. Dipti Patil
 
MULTIMEDIA MODELING
Jasbeer Chauhan
 
DataModelingTechniques.pptx
SriniRao31
 
(Lecture 3) Star Schema.pdf
MobeenMasoudi
 
OracleFIT5195-2-Star Schema.pdfWeek 2 – Star SchemaSe.docx
vannagoforth
 
OracleFIT5195-2-Star Schema.pdfWeek 2 – Star SchemaSe.docx
amit657720
 
Enhanced_Role_of_Schemas_in_Data_Warehouse.pptx
Hardik781481
 

Recently uploaded (20)

PDF
The dynastic history of the Chahmana.pdf
PrachiSontakke5
 
PDF
The Constitution Review Committee (CRC) has released an updated schedule for ...
nservice241
 
PPTX
How to Convert an Opportunity into a Quotation in Odoo 18 CRM
Celine George
 
PPTX
2025 Winter SWAYAM NPTEL & A Student.pptx
Utsav Yagnik
 
PPTX
Cultivation practice of Litchi in Nepal.pptx
UmeshTimilsina1
 
PDF
The Different Types of Non-Experimental Research
Thelma Villaflores
 
PDF
LAW OF CONTRACT ( 5 YEAR LLB & UNITARY LLB)- MODULE-3 - LEARN THROUGH PICTURE
APARNA T SHAIL KUMAR
 
PPTX
How to Create a PDF Report in Odoo 18 - Odoo Slides
Celine George
 
PPTX
A PPT on Alfred Lord Tennyson's Ulysses.
Beena E S
 
PDF
Isharyanti-2025-Cross Language Communication in Indonesian Language
Neny Isharyanti
 
PDF
Dimensions of Societal Planning in Commonism
StefanMz
 
PDF
Women's Health: Essential Tips for Every Stage.pdf
Iftikhar Ahmed
 
PDF
Reconstruct, Restore, Reimagine: New Perspectives on Stoke Newington’s Histor...
History of Stoke Newington
 
PPTX
grade 5 lesson matatag ENGLISH 5_Q1_PPT_WEEK4.pptx
SireQuinn
 
PPTX
I AM MALALA The Girl Who Stood Up for Education and was Shot by the Taliban...
Beena E S
 
PDF
QNL June Edition hosted by Pragya the official Quiz Club of the University of...
Pragya - UEM Kolkata Quiz Club
 
PPTX
Universal immunization Programme (UIP).pptx
Vishal Chanalia
 
PPTX
Growth and development and milestones, factors
BHUVANESHWARI BADIGER
 
PPTX
How to Set Up Tags in Odoo 18 - Odoo Slides
Celine George
 
PPTX
CATEGORIES OF NURSING PERSONNEL: HOSPITAL & COLLEGE
PRADEEP ABOTHU
 
The dynastic history of the Chahmana.pdf
PrachiSontakke5
 
The Constitution Review Committee (CRC) has released an updated schedule for ...
nservice241
 
How to Convert an Opportunity into a Quotation in Odoo 18 CRM
Celine George
 
2025 Winter SWAYAM NPTEL & A Student.pptx
Utsav Yagnik
 
Cultivation practice of Litchi in Nepal.pptx
UmeshTimilsina1
 
The Different Types of Non-Experimental Research
Thelma Villaflores
 
LAW OF CONTRACT ( 5 YEAR LLB & UNITARY LLB)- MODULE-3 - LEARN THROUGH PICTURE
APARNA T SHAIL KUMAR
 
How to Create a PDF Report in Odoo 18 - Odoo Slides
Celine George
 
A PPT on Alfred Lord Tennyson's Ulysses.
Beena E S
 
Isharyanti-2025-Cross Language Communication in Indonesian Language
Neny Isharyanti
 
Dimensions of Societal Planning in Commonism
StefanMz
 
Women's Health: Essential Tips for Every Stage.pdf
Iftikhar Ahmed
 
Reconstruct, Restore, Reimagine: New Perspectives on Stoke Newington’s Histor...
History of Stoke Newington
 
grade 5 lesson matatag ENGLISH 5_Q1_PPT_WEEK4.pptx
SireQuinn
 
I AM MALALA The Girl Who Stood Up for Education and was Shot by the Taliban...
Beena E S
 
QNL June Edition hosted by Pragya the official Quiz Club of the University of...
Pragya - UEM Kolkata Quiz Club
 
Universal immunization Programme (UIP).pptx
Vishal Chanalia
 
Growth and development and milestones, factors
BHUVANESHWARI BADIGER
 
How to Set Up Tags in Odoo 18 - Odoo Slides
Celine George
 
CATEGORIES OF NURSING PERSONNEL: HOSPITAL & COLLEGE
PRADEEP ABOTHU
 
Ad

Schema in Data Mining and Data warehousing

  • 1. SCHEMA BY ANITA DIGGI COURSE:-MCA 3rd College – Srinath University, Adityapur Jamshedpur
  • 2. WHAT IS SCHEMA ? Schema is a logical description of the entire database. It includes the name and description of records of all record types including all associated data-Items and aggregates. Much like a database, a data warehouse also requires to maintain a schema. A database uses relational model, while a data warehouse uses Star, Snowflake, and Fact Constellation schema.
  • 3. TYPES OF SCHEMA Star Schema Snowflake Schema Fact Constellations
  • 4. STAR SCHEMA Each dimension in a star schema is represented with only one-dimension table. A star schema is the elementary form of a dimensional model, in which data are organized into facts and dimensions. There is a fact table at the center. It contains the keys to each of four dimensions. A dimension includes reference data about the fact, such as date, item, or customer. The fact table in a star schema contains the measures or metrics. The dimensional table contain the set of attributes.
  • 5. ADVANTAGES OF STAR SCHEMA Easy for users to understand Queries use very simple joins while retrieving the data and thereby query performance is increased. It is simple to retrieve data for reporting, at any point of time for any period.
  • 6. DISADVANTAGE OF STAR SCHEMA Uses large disk space It can become complex if there are too many dimensions, attributes, rows, or columns in the fact table. Data redundancy is more
  • 8. SNOWFLAKE SCHEMA Represented by centralized fact tables which are connected to multiple dimensions tables. Some dimension tables in the snowflake schema are normalized. A snowflake schema is equivalent to the star schema. A schema is known as a snowflake if one or more dimension table do not connect directly to the fact table but must join through other dimension tables.
  • 9. ADVANTAGE OF SNOWFLAKE SCHEMA Reduces the problem of data integrity Uses small disk space Improvement in query performance Easy to understand It is easy to update (or) maintain the Snow Flaking tables.
  • 10. DISADVANTAGE OF SNOWFLAKE SCHEMA Adds complexity to source query joins Snowflake schemas can have slower data access and queries.
  • 12. FACT CONSTELLATION SCHEMA A fact constellation means two or more fact table sharing one or more dimension. It is a combination of other two schema. A fact constellation has Multiple Fact Table, it is also known as Galaxy Schema.
  • 13. ADVANTAGE OF FACT CONSTELLATION SCHEMA Fact constellation schema can integrate data from multiple sources. It is improved data retrival.
  • 14. DISADVANTAGE OF fact constellation SCHEMA Difficult to maintain More complex than star schema and snowflake schemas