Online Analytical Processing OLAP Anjali Gupta Mithun Arora

Introduction OLAP designates a category of applications and technologies that allow the collection, storage,

RDBMS Month Style Quantity Total Value Jan 2000 Ski Boot 5 1, 700 300

Table Extension… Month Style Outlet Qty. Total Value Jan 2000 Ski Boot HN 3

Why RDBMS fails … n n n 2 -D Structure Multiple Joins and Poor

Consolidation n n Pre-aggregation of all logical subtotals and totals Pre-compute totals by each

Basic Concepts n n n Dimensions Measures Positions Hierarchies Schemas - Star & Snowflake

More Features… n n Formulae Calculations on the fly Drill Down & Roll Up

Different forms of OLAP Three ways of storing data: n n n Multidimensional OLAP

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Online Analytical Processing (OLAP) Anjali Gupta Mithun Arora Aameek Singh Kranthi Kumar 1

Introduction OLAP designates a category of applications and technologies that allow the collection, storage, manipulation and reproduction of multidimensional data, with the goal of analysis. 2

RDBMS Month Style Quantity Total Value Jan 2000 Ski Boot 5 1, 700 300 65, 000 Jan 2000 Gumboot 3

Table Extension… Month Style Outlet Qty. Total Value Jan 2000 Ski Boot HN 3 1300 Jan 2000 Gum. Boots SS 100 18000 4

Why RDBMS fails … n n n 2 -D Structure Multiple Joins and Poor Performance Denormalized Databases Drain Performance & Resources 5

Enter OLAP ! 6

Consolidation n n Pre-aggregation of all logical subtotals and totals Pre-compute totals by each possible subset in the set of dimensions 7

Basic Concepts n n n Dimensions Measures Positions Hierarchies Schemas - Star & Snowflake 8

More Features… n n Formulae Calculations on the fly Drill Down & Roll Up Navigation through levels of detail Slicing & Dicing Pivot / Rotate Change Dimensional Orientation 9

Different forms of OLAP Three ways of storing data: n n n Multidimensional OLAP (MOLAP) Best Query Performance Relational OLAP (ROLAP) Ideal for large databases Hybrid OLAP (HOLAP) Best of both worlds! 10

thank you 11