Databases and Data Warehouses

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

Accuracy - this feature refers to all information being entered accurately in reflection of the relevant collected. For example, the spelling of names correctly is an issue related to the accuracy of information.

Completeness - this characteristic refers to information being completely entered. A common example of this would the entry of addresses, and ensuring all parts of an address are entered; street number, street name and type, city, state and postcode.

Consistency - this characteristic of high quality information refers to information being in agreement with each other, in terms of both content and formatting. An example of this would be the consistent formatting of cells in a spreadsheet containing currency amounts.

Uniqueness - this refers to the duplication of singular transactions, which has the ability to misrepresent store records. An example of this would be ensuring to record a unique customer only once within a database.

Timeliness - this characteristic refers to how up-to-date information is kept, and if this is appropriate in terms of the firm’s requirements. For example, information that must be updated on a regular basis needs to be updated wither daily or hourly, a frequency of which is determined by the firm itself.

Question Two - Define the relationship between a database and a database management system.

A database is an information system that maintains information about object, events, people and places. The database management system is the system which is used when searching, or querying the database for information. The database management system also manages the database to ensure full utilisation.

Question Three - Describe the advantages an organisation can gain by using a database.

Through the use of a database, an organisation can avoid:

• Data redundancy - the storage of the same data in multiple locations, a waste of hard disk space
• Data isolation - where data from one program cannot be accessed by another
• Data inconsistency - where various copies of data do not agree, and employees are presented with the issue of having to determine which is correct.

The use of a database can also ensure that data security (keeping the data safe from theft etc.), integrity (data meeting the constraints of it’s type) and independence (the separation between data and applications) is maintained

Question Four - Define the fundamental concepts of the relational database model.

A relational database is a type of database that stores information in the form of logically related, two dimensional tables. The figure above is one such example of a relational database. The fundamental concepts are:

• Entities - a person, place, object, event or transaction about which information is stored
• Entity Classes - a collection of similar entities
• Attributes - characteristics or properties of an entity class
• Keys - keys within a relational database are divided into two main formats. A primary key is a field that uniquely identifies a given entity in a database table. A foreign key is the primary key of one table that appears as an attribute in another table.
• Relationships - it is the foreign key that provides the relationship between database tables and hence allows a user to search vast amounts of data located in multiple fields with only one query.

Question Five - Describe the benefits of a data-driven website.

A data-driven website is an interactive website that is constantly updated in relation to the relevant needs of the firm’s customers. The benefits of such websites are as follows:

• Development - website owner can make any change at any time.
• Content management - there is no static layer between the website owner and website designer, so content does not have the chance to be misunderstood or slowly updated.
• Future expandability - fast growth is encouraged through data-driven websites.
• Minimisation of human error - data-driven websites have “error-tapping” mechanisms to ensure that all information entered is correct in content and format.
• Cutting of production and update costs - the removal of the middle man (website programmers and developers) cuts costs for any firm.
• Increased efficiency - computer systems are trained to keep record of certain templates and layouts, so that these do not need to be created each time the data-driven website is updated.
• Improved stability - content cannot be lost as there is no need to rely upon layouts specific to programmer’s abilities.

A well known example of a data driven website is Wikipedia, which can be found at the following link: http://en.wikipedia.org/wiki/Main_Page This website is of of many data driven websites, where users have the ability to interact with and modify content as they please. Monitored by administrators, Wikipedia can be likened to a "data farm", where information is created from the infinite amounts of data submitted by users of the website.

Question Six - Describe the roles and purposes of data warehouses and data marts in an organisation.

Data warehouses and data marts play an integral function within organisations, as they are the primary storage facilities for the abundant amounts of data organisations generate on a daily basis. Data warehouses aggregate information into a single repository, making is far more easier for employees to access data, utilise it and assist them in making business decisions and performing business analysis activities. Essentially, instead of the employee looking at a database and calculating totals they may need, an employee can access a data warehouse or data mart to find this information already sorted and organised in a manner appropriate to their need.