Saturday, 17 September 2016

Chapter 8 : Accessing organizational information - Data warehouse.

Learning outcome :
8.1. Describe the roles and purposes of data warehouse and data marts in an organization.
8.2. Compare the multidimensional nature of data warehouse (and data marts) with the two-dimensional nature of database.
8.3. Identify the importance of ensuring the cleanliness of information throughout an organization.
8.4. Explain the relationship between business intelligence and warehouse.

Data Warehouse Fundamentals
  • Data warehouse- is a logical of information which gathered from many different operational databases that supports business analysis activities and decision making task.
  • Database only kept the interesting information.
  • In other words, data warehouse also integrates a logical collection from many different operational databases to support analysis activities and decision making task
  • The primary purpose of a data warehouse is to aggregate information throughout an organizational into a single repository for decision making purpose.
  • Data warehouse modelled compiles information from internal databases or transactional/operational databases and external databases through Extraction, Transformation and Loading (ETL).
  • Extraction, Transformation, and Loading (ETL) is a process that extracts information from internal and external databases.
  • ETL also transform the information using a common set of enterprise definition and loads the information into a data warehouse.
  • A Data Mart contains a subset of data warehouse information.
  • To distinguish data warehouse and data mart, think of data warehouse as having as more organizational focus and data mart as having a focused information subsets particular to the needs of a given business unit such as finance.
 
Multidimensional Analysis and Data mining.
  • A relational database contains information in a series of two-dimensional tables
  • in a data warehouse and data mart, information is multidimensional, meaning that, it contains layers of column and row.
  • Most of data warehouse and data mart are multidimensional databases.
  • A dimension is a particular attribute of information.
  • A cube is the common term for the representation of multidimensional information.
the cube
 
  • A Data Mining is the process of analysing data to extract information not offered by the raw data alone.
  • To perform data mining users need the data-mining tools.
  • Data mining tools use a variety of techniques to find patterns and relationships in large volumes of information and infers rules that predict future behaviour and guide decision making.
  • Data-mining tools for data warehouse and data marts include query tools, reporting tools, multidimensional analysis tools, statistical tools and intelligent agents.
Information Cleansing or scrubbing
  • An organization must maintain high-quality data in the data warehouse.
  • To increase the quality of organizational information and thus the effectiveness of decision making, businesses must formulate a strategy to keep information clean.
  • this is the concept of information cleaning or scrubbing.
  • Information cleansing or scrubbing is a process that weeds out and fixes or discards inconsistent, incorrect, or incomplete information.
  • Specialized software tools use sophisticated algorithms to parse, standardize, correct, match, and consolidate data warehouse information.
  • This is vitally important because data warehouse often contain information from several different databases, some of which from external to the organization.
  • In a data warehouse, information cleansing occurs first during the ETL process.
  • Second  occurs  on the information once it is in the data warehouse.
  • Companies can choose information cleansing software from several different vendors including Oracle, SAS, Ascential software, and Group 1 software.
  • Ideally, scrubbed information is error free and consistent.
Information cleansing activities
  • Missing records or attributes
  • redundant records
  • missing keys or other required data
  • Erroneous relationships
  • Inaccurate data.
Business Intelligence
  • Business Intelligence are the information that people use to support their decision making efforts.
  • The principle of BI enablers include :
- Technology :
  • Even the smallest company with BI software can do sophisticated analyses today that were un available to the largest organization a generation ago.
  • The largest company today can create enterprise-wide BI systems that compute and monitor metrics on virtually every variable important for managing the company.
  • How is this possible? The answer is technology is the most significant enabler of business intelligence.
- People :
  • Understanding the role of people in people in BI allows organizations to systematically create insight and turn these insights into actions.
  • Organizations can improve their decision making by having the right people making the decisions.
  • This usually means a manager who is in the field and close to the customer rather than an analyst rich in data but poor in experience.
- Culture :
  • A key responsibility of executives is to shape and manage corporate culture.
  • the extent to which the BI attitude flourishes in an organization depends in large part of the organization's culture.
  • Perhaps the most important step an organisation can take to encourage BI is to measure the performance of the organization against a set of key indicator.

 


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