Week Seven - Databases and Data Warehouses

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

Characteristics of high quality information:

§  Accuracy – are all the values correct? For example, is the name spelled correctly? Is the dollar amount recorded properly?

§  Completeness – are any of the values missing? For example, is the address complete, including street, city, state, and zip code?

§  Consistency – is aggregate or summary information in agreement with detailed information?

§  Uniqueness – is each transaction, entity, and event represented only once in the information?

§  Timeliness – is the information current with respect to the business requirements? For example, is information updated weekly, daily, or hourly?

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

 

A database management system is the computer program used to manage and query a database. A data base maintains information about various types of objects, events, people and places. Typically a given database has a structural description of the type of facts held in that database, this description is known as a schema.

 

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

 

The advantages an organisation can gain by using a database are:

·       Increased flexibility: a good database can handle changes quickly and easily Databases provide flexibility in allowing each user to access the information in whatever way best sits his or her needs.

·       Increased scalability and performance: Only a database could scale to handle the massive volumes of information and the large numbers of users required. It refers to how well a system can adapt to increased demands and measures how quickly a system performs a certain process or transaction

·       Reduced information redundancy: redundancy is the duplication of information, or storing the same information in multiple places. Redundant information occurs because organisations frequently capture an store the information in multiple locations

·       Increased information integrity: Information integrity is a measure of the quality of information. Within a database environment, integrity constraints are rules that help ensure the quality of information

·       Increased information security: The organisation must protect its information from unauthorised users or misuse.

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

A relational database is a collection of tables from which data can be accessed in many different ways without having to reorganize the database tables. That is, once relationships are created, tables can “talk” to each other.  We can link (relate) the tables to find:

—  Which doctors are seeing a patient

—  Which students are in which class

—  Which item is selling the most on Fridays.

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

Advantages of a data driven website are:

·        Development: allows the website owner to make changes at any time

·         Content management: a static website requires a programmer to make updates

·         Expandability: having a data driven website enables the site to grow faster than would be possible with a static site

·         Minimizing human error: bugs and inconsistencies that can be time consuming and expensive to track down and fix

·         Cutting production and update costs: a data driven website can be updated and published by any competent data entry or administrative person

·         More efficient: computers are excellent at keeping volumes of information in tact

·         Improved stability: any programmer who has o update a website from static templates must be very organized to keep track of all the source files.