Accuracy; Are all the values correct? For example, is the name spelled correctly? Is the dollar amount recorded properly?
Completeness; Are any of the value missing? For example, is the address complete including street, city, state and postcode?
Consistency; Is aggregate or summary information in agreement with detailed information? for example, do all total fields equal the true total of the individual fields?
Uniqueness; Is each transaction, entity and event represented only once in the information? For example, are there any duplicate customers?
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 of a database management system.
A database management system is used to access information from a database. A database management system is software through which users and application programs interact with a database. The user sends requests to the database management system and the database management system performs the actual manipulation of the information in the data base. There are two primary ways that users can interact with a database management system, directly and indirectly.
3. Define the advantages an organisation can gain by using a database.
From a business perspective, database information offers many advantages, including;
Increased flexibility; Databases tend to mirror business structures, and a good database can handle changes quickly and easily, just as any good business needs to be able to handle changes quickly and easily. Equally important, databases provide flexibility in allowing each user to access the information in whatever way best suits his or her needs.
Increased scalability and performance; Only a database could 'scale' to handle the massive volumes of information and the numbers required of for the success of most businesses. Some organisations must be able to support hundreds or thousands of online users including employees, partners, customers and supplier, who all want to access and share information. Databases today scale to exceptional levels, allowing all types of users and programs to perform information processing and information searching tasks.
Reduced information redundancy; One primary goals of a database is to eliminate information redundancy by recording each piece of information in only one place in the database. Eliminating information redundancy saves space, makes performing information updates easier and improves information quality.
Increased information integrity (quality); 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. Integrity constraints can be defined and built into the database design the database ensures users can never violate these constraints.
Increased information security; Information is an organisational asset. Like any asset, the organisation must protect its information from unauthorised users or misuse. Databases offer many security features including passwords, access levels and access controls. Databases can increase personal security as well as informational security.
4. Define the fundamental concepts of the relational database model.
The primary concepts of the relational database model are entities, entity classes, attributes, keys and relationships. An entity in the relational database model is a person, place, thing, transaction or event about which information is stored. A table in the relational database model is a collection of similar entities. Attributes, also called fields, or coloumns, are characteristics or properties o an entity class. Each specific entity in an entity class occupies one row in its respective table. The coloumn in the tables contain attributes.
Development; Allows the website owner to make changes any time, all without having to rely on a developer or knowing HTML programing. A well structured, data driven website enables updating with little or no training.
Content management; A static website requires a programmer to make updates. This add an unnecessary layer between the business and its web content, which can lead to misunderstandings and slow turnarounds fro desired changes.
Future expandability; Having a data driven website enables the site to grow faster than would be possible with a static site. changing the layout, displays and functionality of the site is easier with data driven solutions.
Minimising human error; Even the most competent programmer charged with the take of maintaining many pages will overlook things and make mistakes. this will lead to bugs and inconsistencies that can be time consuming and expensive to track down and fix. Unfortunately,users who come across these bugs will likely become irritated and may leave the site. A well designed, data driven website will have error trapping mechanisms to ensure that required information is filled out correctly and that content is entered and displaced in its correct format.
Cutting production and update costs; A data driven website can be updated and published by any competent data entry or administrative person. In addition to being convenient and more affordable, changes and updates will take a fraction of the time that they would have with a static site. While training a competent programmer can take months or even years, training a data entry person can be done in 30 to 60 minuets.
More efficient; By their very nature, computers are excellent at keeping volumed information only once, in one place, and the site itself will take care of propagating those changes to the appropriate pages and areas. A data driven infrastructure will improve the reliability and satability of a website, while greatly reducing the chance of breaking some part of the site when adding new areas.
Improved stability Any es of information intact. With a data driven solution, the system keeps track of the templates, so users do not have to. Global changes to layout, navigation or site structure would need to be programed by a must be careful to use only the latest version. Withe data driven website, there is a peace of mind, knowing the content is never lost, even if your programme is.
6. Describe the roles and purposes of data warehouses and data marts in an organisation.
Data warehouse; a logical collection of information, gathered from many different operational databases, that supports business analysis activities and decision-making tasks. The primary purpose of a data warehouse is to aggregate information throughout an organisation into a single repository for decision-making purposes.
Data mining; the process of analysing data to extract information not offered by the raw data alone.To perform data mining users need data-mining tools. Data-mining tools helps users uncover business intelligence,for example;
- Cluster analysis
- association detection
- statistical analysis
