What is a Star Schema


Answer posted by Chintan on 2005-05-22 18:34:55: A relational database schema organized around a central table (fact table) joined to a few smaller tables (dimension tables) using foreign key references. The fact table contains raw numeric items that represent relevant business facts (price, discount values, number of units sold, dollar value, etc.)

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Chintan

  • May 22nd, 2005
 

A relational database schema organized around a central table (fact table) joined to a few smaller tables (dimension tables) using foreign key references. The fact table contains raw numeric items that represent relevant business facts (price, discount values, number of units sold, dollar value, etc.)

senthil kumar.B

  • Oct 4th, 2005
 

Star schema is a type of organising the tables such that we can retrieve the result from the database easily and fastly in the warehouse environment.Usually a star schema consists of one or more dimension tables around a fact table which looks like a star,so that it got its name.

Its a type of organising the entities in a way,such that u can retrieve the result from the database easily and very fastly.Usually a star schema will have one or more dimension tables linking around a fact table and looks like a star.hence got this name.

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chandrarekha

  • May 7th, 2007
 

Star schema is a logical data base design, which contains a centrally located fact table surrounded by at least one or more dimension tables

chnadra

  • Apr 17th, 2008
 

A data warehouse design that enhances the performance of multidimensional queries on traditional relational databases. One fact table is surrounded by a series of related tables. Data is joined from one of the points to the center, providing a so-called "star query."

spatnam

  • Dec 9th, 2008
 

Large Central fact table connected to multiple dimension table. Fact having the Foreign key and Dimensions having the Primary key. which resembles as a star.
So the model is named as star schema. primarily used modeling approach for data warehouse.

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tisha24

  • Mar 2nd, 2009
 

Star schema is a simplest form of data warehouse schema., consists of fact tables (possibly one) and referenced by number of dimension tables.  The appearance is like (an centralized fact and surrounded by number of dimensions) a star and hence got the name.

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dxrijesh

  • Jan 16th, 2010
 

It's a logical design techique for a Data Warehousing as fact table in the middle and dimension tables around of it. The Whole model will look like a star having Fact table at the core of the star and dimension table at the spikes of the star.

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A Star Schema is nothing but the Centralized large fact table is connected with all de normalized dimension tables. Hense it looks like Star, so we call this structure as Star Schema.

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Star schema is used in data warehouse models where one centralized fact table references number of dimension tables so as the keys (primary key) from all the dimension tables flow into the fact table (as foreign key) where measures are stored. This entity-relationship diagram looks like a star, hence the name.

Example :

Dimension table (Customer, Product , Time)

Customer
_______________
Cust-Key
Cust-name
Cust-Address
Cust-Status
....
....
....

Product
__________
_____
Prod-Key
Prod-Name
Prod-Category
Prod-price
....
....

Time
_______________
Time-Key
Date
Month
Year


Fact table
_______________

Time-Key
Cust-key
Prod-Key
Quantity
....
....



Customer  ---- Fact table ---- Product
                            |
                            |
                            |
                         Time


Consider a fact table that stores sales quantity for each product and customer on a certain time. Sales quantity will be the measure here and keys from customer, product and time dimension tables will flow into the fact table.

A star-schema is a special case of snow-flake schema.

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Sunil Raina

  • Jul 21st, 2011
 

star schema (also called star-join schema, data cube, or multi-dimensional schema) is the simplest style of data warehouse schema. The star schema consists of one or more fact tables referencing any number of dimension tables. The star schema is an important special case of the snowflake schema, and is more effective for handling simpler queries

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srkreddy

  • Sep 16th, 2011
 

star schema defined as,A fact table is surrounded my many multiple dimension tables.
(it means all dimension tables directly maintains relationship with the fact tables in this schema)

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TimeBeing

  • Jan 25th, 2017
 

A Fact table is surrounded by multiple Dimension tables and which is look like STAR in graphical design is called "STAR Schema".

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kamesh

  • Jan 30th, 2018
 

A join is linked with only one dimension and one fact is called Star chema

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