Data Warehousing Datamining Concepts by IIT Mumbai

1. DATA WAREHOUSING AND DATA MINING S. Sudarshan Krithi Ramamritham IIT Bombay [email_address] [email_address]

4. A producer wants to know…. Which are our lowest/highest margin customers ? Who are my customers and what products are they buying? Which customers are most likely to go to the competition ? What impact will new products/services have on revenue and margins? What product prom- -otions have the biggest impact on revenue? What is the most effective distribution channel?

10. Warehouses are Very Large Databases 35% 30% 25% 20% 15% 10% 5% 0% 5GB 5-9GB 10-19GB 50-99GB 250-499GB 20-49GB 100-249GB 500GB-1TB Initial Projected 2Q96 Source: META Group, Inc. Respondents

14. Explorers, Farmers and Tourists Explorers: Seek out the unknown and previously unsuspected rewards hiding in the detailed data Farmers: Harvest information from known access paths Tourists: Browse information harvested by farmers

15. Data Warehouse Architecture Data Warehouse Engine Optimized Loader Extraction Cleansing Analyze Query Metadata Repository Relational Databases Legacy Data Purchased Data ERP Systems

20. Application Areas Industry Application Finance Credit Card Analysis Insurance Claims, Fraud Analysis Telecommunication Call record analysis Transport Logistics management Consumer goods promotion analysis Data Service providers Value added data Utilities Power usage analysis

27. Examples of Operational Data Data Industry Usage Technology Volumes Customer File All Track Customer Details Legacy application, flat files, main frames Small-medium Account Balance Finance Control account activities Legacy applications, hierarchical databases, mainframe Large Point-of- Sale data Retail Generate bills, manage stock ERP, Client/Server, relational databases Very Large Call Record Telecomm- unications Billing Legacy application, hierarchical database, mainframe Very Large Production Record Manufact- uring Control Production ERP, relational databases, AS/400 Medium

28. So, what’s different?

29. Application-Orientation vs. Subject-Orientation Application-Orientation Operational Database Loans Credit Card Trust Savings Subject-Orientation Data Warehouse Customer Vendor Product Activity

43. Data Warehouse Architecture Data Warehouse Engine Optimized Loader Extraction Cleansing Analyze Query Metadata Repository Relational Databases Legacy Data Purchased Data ERP Systems

45. Loading the Warehouse Cleaning the data before it is loaded

49. Data Integration Across Sources Trust Credit card Savings Loans Same data different name Different data Same name Data found here nowhere else Different keys same data

50. Data Transformation Example encoding unit field appl A - balance appl B - bal appl C - currbal appl D - balcurr appl A - pipeline - cm appl B - pipeline - in appl C - pipeline - feet appl D - pipeline - yds appl A - m,f appl B - 1,0 appl C - x,y appl D - male, female Data Warehouse

66. Structuring/Modeling Issues

73. Vertical Partitioning Frequently accessed Rarely accessed Smaller table and so less I/O Acct. No Name Balance Date Opened Interest Rate Address Acct. No Balance Acct. No Name Date Opened Interest Rate Address

88. Data Warehouse vs. Data Marts What comes first

89. From the Data Warehouse to Data Marts Departmentally Structured Individually Structured Data Warehouse Organizationally Structured Less More History Normalized Detailed Data Information

90. Data Warehouse and Data Marts OLAP Data Mart Lightly summarized Departmentally structured Organizationally structured Atomic Detailed Data Warehouse Data

93. Data Mart Centric Data Marts Data Sources Data Warehouse

94. Problems with Data Mart Centric Solution If you end up creating multiple warehouses, integrating them is a problem

95. True Warehouse Data Marts Data Sources Data Warehouse

100. Bitmap Index Customer Query : select * from customer where gender = ‘F’ and vote = ‘Y’ gender (f) vote (y) result vote gender 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 M F F F F M Y Y Y N N N

101. Bit Map Index Base Table Rating Index Region Index Customers where Region = W Rating = M And

106. Optimized Star Join Processing Virtual Cross Product of T, L and P Apply Selections Time Loca- tion Plan Calls

107. Bitmapped Join Processing AND Time Loca- tion Plan Calls Calls Calls Bitmaps 1 0 1 0 0 1 1 1 0

117. Using SubQueries in Calculations select product, dollars as jun97_sales, (select sum(s1.dollars) from market mi, product pi, period, ti, sales si where pi.product = product.product and ti.year = period.year and mi.city = market.city) as total97_sales, 100 * dollars/ (select sum(s1.dollars) from market mi, product pi, period, ti, sales si where pi.product = product.product and ti.year = period.year and mi.city = market.city) as percent_of_yr from market, product, period, sales where year = 1997 and month = ‘June’ and city like ‘Ahmed%’ order by product;

119. II. On-Line Analytical Processing (OLAP) Making Decision Support Possible

128. Visualizing Neighbors is simpler

129. A Visual Operation: Pivot (Rotate) 10 47 30 12 Juice Cola Milk Cream NY LA SF 3/1 3/2 3/3 3/4 Date Month Region Product

130. “Slicing and Dicing” Product Sales Channel Regions Retail Direct Special Household Telecomm Video Audio India Far East Europe The Telecomm Slice

137. Relational OLAP: 3 Tier DSS Store atomic data in industry standard RDBMS. Generate SQL execution plans in the ROLAP engine to obtain OLAP functionality. Obtain multi-dimensional reports from the DSS Client. Data Warehouse ROLAP Engine Decision Support Client Database Layer Application Logic Layer Presentation Layer

138. MD-OLAP: 2 Tier DSS MDDB Engine MDDB Engine Decision Support Client Database Layer Application Logic Layer Presentation Layer Store atomic data in a proprietary data structure (MDDB), pre-calculate as many outcomes as possible, obtain OLAP functionality via proprietary algorithms running against this data. Obtain multi-dimensional reports from the DSS Client.

139. Typical OLAP Problems Data Explosion Data Explosion Syndrome Number of Dimensions Number of Aggregations (4 levels in each dimension) Microsoft TechEd’98

142. Recipe for a Successful Warehouse

151. Products, References, Useful Links