Multidimensional Database in Multidimensional Database in Context of DB2 OLAP ServerContext of DB2 OLAP Server

Khang Pham

Class: CSCI397-16C

Instructor: Professor Renner

Why Multidimensional DatabaseWhy Multidimensional Database

Need of a business modelQuick access to dataNeed of view data

DB2 OLAP SERVERDB2 OLAP SERVER

Provide an abstraction of a multidimensional database on top of relational storage.

Allowing quick access to data. Reliable storage. Close integration with warehouse data.

Architecture:Architecture:

Consist of 3 major components:1) Application Manager and Excel Plug-in2) Essbase Server3) DB2

Example Example (page1)(page1)

Application Manager: Build the Model

Example Example (page2)(page2)

Application manager: import data

Example Example (page 3)(page 3)

Text Data File

Example Example (page 4)(page 4)

Application Manager: calculate data

Example Example (Page 5)(Page 5)

Excel Plug-in: showing data

Storage ManagerStorage Manager

FunctionalityImplementation

- Overview- Concept of Dense and Sparse dimension- Star Schema- Actual Storage

Overview: mapping multidimensional Overview: mapping multidimensional data to linear data. data to linear data.

Physical storage are linear.We have to map multidimensional data

to linear data in order to store it.Approach:

- An array x[width][height] can be stored as x[width*height].- Indexing element x[m][n] can be treated as indexing x[m*width+n]- Expanding this concept to store multidimensional data

Dense and Sparse ConceptDense and Sparse Concept

Structures are too big to store Mostly are missing data cells Idea: don’t store missing data cells Dense Dimension: densely populated Sparse Dimension: sparsely populated Block: data block made of dense dimensions Only allocate block that has data Index data block by sparse dimensions Greatly reduce storage space

Star SchemaStar Schema

Consists of one central table that holds all the data -- Fact table.

Surrounded by dimension tables.Joint dimension table and fact table

to get the view of data on this dimension.

DB2 is optimized for executing these joint query.

Actual StorageActual Storage

The structure of fact table- Columns consist of:

. All members of one chosen dimension.

. Key columns (one per sparse dimension).

- Key composed of the key columns

SummarySummary

A Great business solution- Quickly build your model- Quickly get to your business decision

Multidimensional view of data- Locating data of interest- Making report, statistics ...etc.

Have all relational features- Select, replicate, back up ...etc.

ReferencesReferences

Websites:http://www-4.ibm.com/software/data/db2/db2olap/http://www-4.ibm.com/software/data/db2/http://www.software.ibm.com/http://www.hyperion.com/essbaseolap.cfm

Books and writings:Arbor Essbase Version 5: Database Administrator's Guide Volume I, copyright 1991-1997 Arbor Software Corporation, P/N: 06070-500000-000.Arbor Essbase Version 5: Database Administrator's Guide Volume II, copyright 1991-1997 Arbor Software Corporation, P/N: 06071-500000-000.DB2 OLAP Server Fundamentals, copyright 1998 IBM corporation.IBM DB2 OLAP Server: Using DB2 OLAP Server (Version 1.0.1), copyright 1998 IBM corporation, SC26-9235-01.

Software packages and tutorials:DB2 Universal Database 6.1 Trial Version, copyright IBM Corporation 1999.DB2 OLAP Server 1.1 Trial Version, copyright IBM Corporation 1999.