Chapter Eight

Accessing organization information- data warehouse


1. Data warehouse

-A decision support database that is maintained separately from the organization’s operational database.
-A consistent database source that bring together information from multiple sources for decision support queries.
-Support information processing by providing a solid platform of consolidated, historical data for analysis.




2. History of data warehouse

-In the 1990’s executives became less concerned with the day-to-day business operations and more concerned with overall business functions.
-The data warehouse provided the ability to support decision making without disrupting the day-to-day -operations, because;

Operational information is mainly current – does not include the history for better decision making
- Issues of quality information
- Without information history, it is difficult to tell how and why things change over
time


3. Data warehouse fundamentals.

-Data warehouse – A logical collection of information, gathered from many different operational databases, .that supports business analysis activities and decision-making takes.

-The primary purpose of a data warehouse is to combined information throughout an organization into a single repository for decision-making purposes – data warehouse support only analytical processing


4. Data warehouse model.

-Extraction, transformation and loading (ETL) – A process that extracts information from internal and external databases, transforms the information using a common set of enterprise definitions, and loads the information into a data warehouse.
-Data warehouse then send subsets of the information to data mart.
-Data mart – contains a subset of data warehouse information.







5. Multidimensional  analysis and mining.

-Relational Database contains information in a series of two-dimensional tables.
-In a data warehouse and data mart, information is multidimensional, it contains layers of columns and rows
- Dimension – A particular attribute of information.





Cube – common term for the representation of multidimensional information.




-Once a cube of information is created, users can begin to slice and dice the cube to drill down into the information.

-Users can analyze information in a number of different ways and with number of different dimensions.

-Data Mining – the process of analyzing data to extract information not offered by the raw data alone. Also known as “knowledge discovery” – computer-assisted tools and techniques for sifting through and analyzing vast data stores in order to finds trends, patterns and correlations that can guide decision making and increase understanding.

-To perform data mining users need data-mining tools
- Data-mining tool – uses a variety of techniques to finds patterns and relationships in large volumes of information. Eg: retailers and use knowledge of these patterns to improve the placement of items in the layout of a mail-order catalog page or Web page.



6. Information cleansing or scrubbing.

-An organization must maintain high-quality data in the data warehouse.
-Information cleansing or scrubbing – A process that weeds out and fixes or discards inconsistent, incorrect or incomplete information.
-Occurs during ETL process and second on the information once if is in the data warehouse.
-Contract information in an operational system.
-Standardizing customer;s name from Operational Systems.
-Information cleansing activities
- Missing Records or Attributes
- Redundant Records
- Missing Keys or Other Required Data
- Erroneous Relationships or References
- Inaccurate Data


Accurate and complete information





7. Business intelligence

-Business Intelligence – refers to applications and technologies that are used to gather, provides access, analyze data and information to support decision making efforts.

-These systems will illustrate business intelligence in the areas of customer profiling, customer support, market research, market segmentation, product profitability, statistical analysis, and inventory and distribution analysis to name a few.