1. What is OLAP?

2. What is OLAP?
OLAP stands for the Online Analytical Processing that is used to create decision support software
OLAP enables application users to quickly analyze information that has been summarized into multidimensional views and hierarchies

3. By summarizing predicted queries into multidimensional views prior to run time.
OLAP tools provide the benefit of increased performance over traditional database access tools.
Most of the resource-intensive calculation that is required to summarize the data is done before a query is submitted

4. BENEFITS OF OLAP
Fast access, calculations, and summaries of an organization's data
support for multiple user access and multiple queries
Ability to handle multiple hierarchies and levels of data
Ability to presummarize and consolidate data for faster query and reporting functions
Ability to expand the number of dimensions and levels of data as a business grows

5. Relational OLAP(ROLAP) Multidimensional OLAP(MOLAP) Hybrid OLAP(HOLAP)
Types of OLAP
Relational OLAP(ROLAP)
Multidimensional OLAP(MOLAP)
Hybrid OLAP(HOLAP)

6. Relational OLAP

7. Relational OLAP
Provide functionality by using relational database and relational query tool to store and analyze multidimensional data.
Build an existing relational technologies and represent extension to all those companies who already used RDBMS

8. Multidimensional data schema support with the RDBMS
Data access language and query performance are optimized for multidimensional data.
Support for very large databases.

9. Implementation of OLAP server
Data is stored in tables in relational database extended relational database.
They use an RDBMS to manage the warehouse data and aggregation using often a star schema

10. Advantages Scalable Handle large amount of data
Leverage functionalities inherent in the relational database

11. Disadvantages Performance can be slow Direct access to cell
Limited by SQL functionality

12. Multidimensional OLAP(MOLAP)

13. MOLAP is a "multi-dimensional online analytical processing"
MOLAP is a "multi-dimensional online analytical processing". 'MOLAP' is the 'classic' form of OLAP and is sometimes referred to as just OLAP. MOLAP stores this data in an optimized multi-dimensional array storage, rather than in a relational database. Therefore it requires the pre-computation and storage of information in the cube - the operation known as processing.

14. TOOL
MOLAP tools generally utilize a pre-calculated data set referred to as a data cube. The data cube contains all the possible answers to a given range of questions. MOLAP tools have a very fast response time and the ability to quickly write back data into the data set.

15. Advantages
Excellent performance: MOLAP cubes are built for fast data retrieval.
Can perform complex calculations: All calculations have been pre-generated when the cube is created.

16. .
Disadvantages
Only summary-level information will be included in the cube itself.
Store Limited range of data.

17. Hybrid OLAP (HOLAP)

18. HOLAP is the product of the attempt to incorporate the best features of MOLAP and ROLAP into a single architecture.
This tool tried to bridge the technology gap of both products by enabling access or use to both multidimensional database (MDDB) and Relational Database Management System (RDBMS) data stores.

19. HOLAP systems stores larger quantities of detailed data in the relational tables while the aggregations are stored in the pre-calculated cubes.
For summary-type information, HOLAP leverages cube technology for faster performance. When detail information is needed, HOLAP can "drill through" from the cube into the underlying relational data.

20. Advantages of HOLAP Better scalability Quick data processing
Flexibility in accessing of data sources

21. The Microsoft SQL Server 7
The Microsoft SQL Server 7.0 OLAP Services supports a hybrid OLAP server.