Weekly Questions Week 7

Weekly Questions (Week 7)

Chapter 6: Databases And Data Warehouses

Database(Diagram 1)

1. List, describe, and provide an example of each of the five characteristics of high quality information.

Accuracy – are values input correct e.g. correct spelling of names, addresses and phone numbers

Completeness – missing or incomplete values e.g. missing first names, phone numbers, email address

Consistency – standard of data input is kept the same for particular values e.g. standard date format, capital letters for names

Uniqueness – no duplication in data, whereby data such as events and transactions are represented only once in information e.g. duplicate customers 

Timeliness – is the information current (up-to-date)? e.g. changes in customer phone numbers or addresses

For further information, visit: 

http://sites.google.com/site/b188sjsu/Home/database/five-characteristics-of-high-quality-information

2. Define the relationship between a database and a database management system.

A database is a system used to store and organise important information through the use of fields, records and 2 dimensional tables. Data stored could include sales data, inventory data, transactions and people. Database management systems are programs used in the creation and maintenance of databases, and allow multiple users to access, store and retrieve information from a database. 

Database Management System (Diagram 2)

  For further information, visit:

http://en.wikipedia.org/wiki/Database_management_systems

http://www.webopedia.com/TERM/D/database_management_system_DBMS.html

3. Describe the advantages an organisation can gain by using a database.

Advantages gained from the use of Databases include:

Database made up of many records and tables

(Diagram 3)

• Increased flexibility – Able to update and change data easily and quickly. An individual only needs to input data once in the database and this transfers to various areas. The user can search for specific information more easily.

• Reduced information redundancy - Reduces duplication and storage of information in multiple areas which results in inconsistencies.

• Increased information quality – As a result of ‘Relational integrity constrains’ and ‘business- critical integrity constraints’, data entered must meet specific requirements (e.g. 10 digits). As such, this will keep a high quality standard throughout the database. 

• Increased information security – Makes data more secure because databases allow authorisation and authentication, limiting the information available to only approved individuals  

4. Define the fundamental concepts of the relational database model.

Relational Database Model (Diagram 4)

A relational database model contains many records and 2 dimensional tables. These 2 dimensional tables are then joined together, which enables an individual to find specific information, without having to alter table formats. In relational databases, primary and foreign keys must be established in order to form a relationship between data. Primary keys have great importance as they are used to identify entities (e.g. customer ID). "Primary keys in one table which appear as an attribute on another are called foreign keys"(Baltzan, Philips, Lynch & Blakey 2010).As such, this provides a link between data (tables), allowing a user to find information needed.   

For further information, visit:

http://www.ibm.com/developerworks/library/x-matters8/index.html

5. Describe the benefits of a data-driven website.

• Development – Changes and updates to a website can be made by the business owner with ease.

• Future expandability – website is able to grow at a fast rate because of the ease of adding and modifying page layouts, features and functions on a website

• Content management & Minimizing human error – Data is entered once, thereby reducing information redundancy

• Cutting production and update costs – Altering and updating a data driven website is more cost effective and less time consuming then altering a static website. A data driven sites can be altered by a competent administrative person who could be trained within a day. However, a programmer’s training would take months, adding to the cost of the business.

• More efficient- Site Layouts, features and structures would only need to be altered once and these changes will be implemented to the areas and pages necessary. A data driven infrastructure not only saves time when making alterations, but also improves the reliability and stability

• Improved stability –programmers need to be organized and careful when altering a static page because if careless, they will be unable to locate source files resulting in the creation of existing work. However, in a data driven site, information will never be lost.
  
  
  6. Describe the roles and purposes of data warehouses and data marts in an organisation
  A Data warehouse is a collection of information from many databases which are used to support decision making tasks. Although databases store important information, the main role of a datahouse is to store, combine and summaries this information in a way which can be used by business personnel to make informed decisions. Similarly, Data mining “is the process of analysing data to extract information not offered by raw data alone” (Baltzan, Phillips, Lynch, Blakey 2010).As such, both datahouses and mining play an important role in an organisation because they provide personnel with important information which can be used to assist them in decision making and analytical activities.
  
  For further information, visit:
  
  

  http://en.wikipedia.org/wiki/Data_warehouse  
  http://www.webopedia.com/TERM/D/data_warehouse.html

  http://www.webopedia.com/TERM/D/data_mart.html
  Images References
  Diagram 1:http://www.heidibrebels.be/blog/archives/2011/multiple-rows-in-one-column-sql/
  Diagram 2:http://ironbark.bendigo.latrobe.edu.au/subjects/DB/2010s2/lectures/lecture01.html 
  Diagram 3: http://as-infotech.com/DatabaseManagement.asp
  Diagram 4:http://www.ibm.com/developerworks/library/x-matters8/index.html