On-Line Analytical Processing (OLAP)

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On-Line Analytical Processing(OLAP)
Theodoros Chrysafis Department of Computer
Science CITY Liberal Studies an Affiliated
Institution of the University of
Sheffield Academix 2003
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Contents

• Introduction
• Decision Support Systems
• On-Line Analytical Processing (OLAP)
• OLAP Taxonomy
• MOLAP
• ROLAP
• HOLAP
• DOLAP
• Conclusion

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Introduction

• What is
• On-Line A process controlled by a computer.
• Analytical Processing needs Analytical Data.
• Analytical Data Data that involve analysis.
• Analytical Data consist of Business Data.
• Business Data Time, Customers, Sales, Stores,
  Products, etc.

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Decision Support Systems

• Decision Support Systems (DSS) can defined in two
  ways
• By describing the software tools or the
  technologies we use to perform business
  decisions.
• OR
• By describing the function or the concept of
  Decision Support Systems in a tool neutral way.

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Decision Support Systems

• Definition of DSS by Erik Thomsen
• The activity of using logic-based
  fact-processing rules in combination with
  goal-oriented management rules with or without
  human intervention to translate larger sets of
  lower-level facts and fact relationships into
  smaller sets of higher-level facts and fact
  relationships (and vise versa).

Client
Analytical Processing
Analytical Data
Business Data
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Decision Support Systems

• DSS treats facts and rules differently. This
  treatment groups DSS in the following categories
• Data Mining Tools - Discover rules that explain
  relationships between facts.
• OLAP Tools - organise facts according to multiple
  dimensions and they use powerful rules for
  combining those facts to form aggregate facts.
• Business Modeling Tools - organise the management
  and the expert tools.
• Data Visualisation Tools - graphically illustrate
  relationships between facts.

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Data Dimensionality
Customers
Sale

• Possible Views of Sale
• How many Products sold at Time to specific
  Customer(s)?
• How many Customers bought at specific Time the
  Product(s)?
• At which Time(s) the Customer(s) bought the
  specific Product(s)?

• Products

Time
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On-Line Analytical Processing

• On-Line Analytical Processing (OLAP) definition
  by OLAP Council
• A category of software technology that enables
  analysts, managers and executives to gain insight
  into data through fast, consistent, interactive
  access to a wide variety of possible views of
  information that has been transformed from raw
  data to reflect the real dimensionality of the
  enterprise us understood by the user.

Security
Interactivity
Customisation
Visualisation
OLAP
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On-Line Analytical Processing

• OLAP functionality provides dynamic
  multi-dimensional analysis, supporting analytical
  and navigational activities.
• OLAP functionality is provided by the OLAP
  Server.
• OLAP Council defines OLAP Server as A high
  capacity, multi-user data manipulation engine
  specifically designed to support and operate on
  multi-dimensional data structures.

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On-Line Analytical Processing

• OLAP Taxonomy
• Multi-dimensional OLAP (MOLAP)
• A k-dimensional matrix based on a non relational
  storage structure. Agrawal et al.
• Relational OLAP (ROLAP)
• A relational back-end wherein operations of the
  data are translated to relational queries.
  Agrawal et al.
• Hybrid OLAP (HOLAP)
• Integration of MOLAP and ROLAP.
• Desktop OLAP (DOLAP)
• Provides a specific cube for analysis. Simplified
  version of MOLAP or ROLAP.

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On-Line Analytical Processing

• MOLAP
• Multi-dimensional data management in
  Multi-Dimensional Database Management Systems
  (MDDBMS).
• Advantages Fast data access, many dimensions,
  performance.
• Further Research on storage techniques and
  realisation of transactional concepts.

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On-Line Analytical Processing

• ROLAP
• A multi-dimensional user view on relational data
  storage using Star or Snowflake Database Schemata.

Region Dimension
Customer Dimension
Product Dimension
Time Dimension
Snowflake Schema
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On-Line Analytical Processing

• ROLAP
• Advantages Easy to understand, easy to model,
  easy to implement.
• Further Research on dynamic optimisation, on
  meta-models, on functional extensions for the
  ROLAP engines, on user-defined functions for the
  OLAP.

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On-Line Analytical Processing

• HOLAP
• A system, which supports (and integrates)
  multi-dimensional and relational storage for data
  in an equivalent manner in order to benefit from
  the corresponding characteristics and
  optimisation techniques. Dinter et al.
• Advantages use of best techniques introduced on
  MOLAP and ROLAP, transparency between MOLAP and
  ROLAP systems.
• Further Research on storage systems, on global
  multi-dimensional schema, on common interface and
  mutual integration of MOLAP and ROLAP.

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On-Line Analytical Processing

• Conclusion
• OLAP Tools are Market Driven. That is, no
  standards either academic or from an organisation
  exist.
• A common model approach is to use Star or
  Snowflake Database Schemata (common in Data
  Warehouse Modeling).
• Reviews contain many technical issues resulting
  difficulties to understand while a candidate end
  user needs information about a candidate product.
• Hence, we advice candidate end users to look for
  the following, independent tool architecture or
  vendor, characteristics.

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On-Line Analytical Processing

• Conclusion
• Interactivity How easy the end user interacts
  with the tool?
• Customisation How easy the end user make
  changes on the data representation provided by
  the tool?
• Security How easy the end user can access
  unauthorised data?
• Visualisation How easy the tool provide
  multi-dimensional graphical representations?

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Thank you for your attention!
Any Questions?