on-line analytical processing (olap)...
TRANSCRIPT
![Page 1: On-Line Analytical Processing (OLAP) Introductionopenclassroom.stanford.edu/.../cs145/old-site/docs/pdfs/OLAPIntro.pdf · Jennifer Widom More terminology Data warehousing Bring data](https://reader031.vdocument.in/reader031/viewer/2022031012/5b96ba9a09d3f27e758be7d3/html5/thumbnails/1.jpg)
Jennifer Widom
On-Line Analytical Processing (OLAP)
Introduction
![Page 2: On-Line Analytical Processing (OLAP) Introductionopenclassroom.stanford.edu/.../cs145/old-site/docs/pdfs/OLAPIntro.pdf · Jennifer Widom More terminology Data warehousing Bring data](https://reader031.vdocument.in/reader031/viewer/2022031012/5b96ba9a09d3f27e758be7d3/html5/thumbnails/2.jpg)
Jennifer Widom
OLAP: Intro Two broad types of database activity
OLTP – Online Transaction Processing – Short transactions – Simple queries – Touch small portions of data – Frequent updates
OLAP – Online Analytical Processing – Long transactions – Complex queries – Touch large portions of the data – Infrequent updates
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Jennifer Widom
More terminology
Data warehousing Bring data from operational (OLTP) sources into a single
“warehouse” for (OLAP) analysis
Decision support system (DSS) Infrastructure for data analysis E.g., data warehouse tuned for OLAP
OLAP: Intro
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Jennifer Widom
“Star Schema”
Fact table Updated frequently, often append-only, very large
Dimension tables Updated infrequently, not as large
OLAP: Intro
![Page 5: On-Line Analytical Processing (OLAP) Introductionopenclassroom.stanford.edu/.../cs145/old-site/docs/pdfs/OLAPIntro.pdf · Jennifer Widom More terminology Data warehousing Bring data](https://reader031.vdocument.in/reader031/viewer/2022031012/5b96ba9a09d3f27e758be7d3/html5/thumbnails/5.jpg)
Jennifer Widom
Star Schema – fact table references dimension tables OLAP: Intro
Sales(storeID, itemID, custID, qty, price)
Store(storeID, city, state)
Item(itemID, category, brand, color, size)
Customer(custID, name, address)
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Jennifer Widom
OLAP queries
Join Filter Group Aggregate
Performance – Inherently very slow: special indexes, query processing techniques
– Extensive use of materialized views
OLAP: Intro
Sales(storeID, itemID, custID, qty, price)
Store(storeID, city, state)
Item(itemID, category, brand, color, size)
Customer(custID, name, address)
![Page 7: On-Line Analytical Processing (OLAP) Introductionopenclassroom.stanford.edu/.../cs145/old-site/docs/pdfs/OLAPIntro.pdf · Jennifer Widom More terminology Data warehousing Bring data](https://reader031.vdocument.in/reader031/viewer/2022031012/5b96ba9a09d3f27e758be7d3/html5/thumbnails/7.jpg)
Jennifer Widom
Data Cube (a.k.a. multidimensional OLAP) Dimension data forms axes of “cube” Fact (dependent) data in cells Aggregated data on sides, edges, corner
OLAP: Intro
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Jennifer Widom
Fact table uniqueness for data cube
If dimension attributes not key, must aggregate
Date can be used to create key Dimension or dependent?
OLAP: Intro
Sales(storeID, itemID, custID, qty, price)
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Jennifer Widom
Drill-down and Roll-up OLAP: Intro
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Jennifer Widom
Drill-down and Roll-up Examining summary data, break out by dimension attribute
OLAP: Intro
Select state, brand, Sum(qty*price)
From Sales F, Store S, Item I
Where F.storeID = S.storeID And F.itemID = I.itemID
Group By state, brand
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Jennifer Widom
Drill-down and Roll-up Examining data, summarize by dimension attribute
OLAP: Intro
Select state, brand, Sum(qty*price)
From Sales F, Store S, Item I
Where F.storeID = S.storeID And F.itemID = I.itemID
Group By state, brand
![Page 12: On-Line Analytical Processing (OLAP) Introductionopenclassroom.stanford.edu/.../cs145/old-site/docs/pdfs/OLAPIntro.pdf · Jennifer Widom More terminology Data warehousing Bring data](https://reader031.vdocument.in/reader031/viewer/2022031012/5b96ba9a09d3f27e758be7d3/html5/thumbnails/12.jpg)
Jennifer Widom
SQL Constructs
With Cube and With Rollup
Add to result: faces, edges, and corner of cube using NULL values
OLAP: Intro
Select dimension-attrs, aggregates
From tables
Where conditions
Group By dimension-attrs With Cube
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Jennifer Widom
SQL Constructs
With Cube and With Rollup
For hierarchical dimensions, portion of With Cube
OLAP: Intro
Select dimension-attrs, aggregates
From tables
Where conditions
Group By dimension-attrs With Rollup
![Page 14: On-Line Analytical Processing (OLAP) Introductionopenclassroom.stanford.edu/.../cs145/old-site/docs/pdfs/OLAPIntro.pdf · Jennifer Widom More terminology Data warehousing Bring data](https://reader031.vdocument.in/reader031/viewer/2022031012/5b96ba9a09d3f27e758be7d3/html5/thumbnails/14.jpg)
Jennifer Widom
OLAP: Intro Two broad types of database activity
OLTP – Online Transaction Processing – Short transactions – Simple queries – Touch small portions of data – Frequent updates
OLAP – Online Analytical Processing – Long transactions – Complex queries – Touch large portions of the data – Infrequent updates
Star schemas Data cubes With Cube and With Rollup Special indexes and query processing techniques