a) Accuracy – This refers to how correct the information is. For example, have all of the names been spelled correctly and is the amount that is entered correct?
b) Completeness – Refers to whether or not the data base is complete or whether some fields are still requiring data to be entered. For example, is the address complete with street name, city, state and postcode included?
c) Consistency – This refers to whether or not the data presented in a field is consistent with other fields. For example, do all the totals presented in a field reflect the true total?
d) Uniqueness – This refers to whether or not the data has only been entered once or has been repeated throughout the data base. For example, are there any duplicate customers?
e) Timeliness – This refers to how often the data in the data base is updated. For example, is the data updated daily, weekly or monthly?
2. Define the relationship between a database and a database management system.
- A database is the key to an organisation. It stores information on people, places, events and objects, for example employee data, financial records, etc. the schema of a database describes the objects in a database and the relationship between them.
- A database management system (DBMS) is the program that is used to monitor the database. It allows all users to be able to access the data. A DBMS allows users to produce reports, as well as manage the in-put and out-put of data.
3. Describe the advantages an organisation can gain by using a database.
Example of a database:
http://www.qweas.com/download/business/database_management/screen/mobile_database_viewer_access_xls_oracle_2.jpg
The advantages to an organisation of using a database include:
- Increased flexibility – A good database is able to handle changes quickly and easily, as well as allowing users to access this information in a way that suits their needs.
- Increased scalability and performance – Scalability means how well a business is able to adapt to changes and increased demands. Performance means how well a system is able to perform a process or transaction. A good database will be able to keep up with the increased demand.
- Reduced information redundancy – Redundancy is the duplication of information or the storing of information in multiple places. With the same information being stored in multiple locations, it makes it difficult to determine which values are the most current and accurate. Through the elimination of information redundancy, it records each piece of data in the same space, which saves space making information updates easier and the information quality increases.
- Increases information integrity (quality) – Information integrity measures the quality of the information. Integrity constraints ensure the quality of information, which are able to be built in the database design. The database ensures that the user is not able to violate these constraints
- Increased information security – Information to an organisation is like an asset and needs to be protected from unauthorised users or misuse. Databases can protect this data through passwords (provide authentication to the user who is accessing the data), access levels (who has access to what information) and access controls (what type of access they have to the information).
4. Define the fundamental concepts of the relational database model.
Example of a Relational Database Model
http://www.databasedev.co.uk/image/holiday_cottage_bookings_data_model.gif
A relational database model is a database that stores information in the form of two-dimensional tables each consisting of rows and columns. It is the most commonly used database today, with each of the tables logically relating to each other.
The primary concepts of a relational database model are entities, which are a person, place, thing, transaction or event about which the information is stored, entity classes, attributes (fields or columns), which are the characteristics or properties of an entity class, keys and relationships. To be able to manage and organise the entity classes, the primary keys and foreign keys must be identified and used to create logical relationships. A primary key is a field that identifies a given entity in a table, while a foreign key is a primary key of one table that appears as an attribute in another table and provides a logical relationship between the two tables.
5. Describe the benefits of a data-driven website.
Example of a Data-driven Website
http://images.cowlesgraphicdesign.com/websites/district46.jpg
A data driven website is an interactive website that is constantly kept updated and is relevant to the needs of its customers through the use of a database. They are useful when the site offers a great deal of information, products or services. It works through the user entering a query and the relevant data coming up, for example Wikipedia.
The advantages of a data-driven website are:
- Information is able to be updated and changes made at any time, with little to no training required.
- A data-driven website allows the site to grow faster. The layout, displays and functionality of the site is easy.
- A well-designed data-driven website will have ‘error-trapping’ mechanisms to ensure that the information is filled out correctly and the content is entered and displayed in the correct format.
- Changes made to a data-driven website are easy, cutting time and cost. Training on how to use is minimal.
- Changes to the layout, navigation or site structure only need to be programmed once. A data-driven infrastructure improves the reliability and stability of a website while reducing the chance of it ‘breaking’.
- Content on the website is never lost
- A query or search is able to be made on the website with all information relating to the query returned.
- Increases customer satisfaction
6. Describe the roles and purposes of data warehouses and data marts in an organization.
A data warehouse is a logical collection of information that is gathered from many different operational databases and supports the business analysis activities and decision-making tasks (a large collection of many databases). A data mart is a smaller subset of a data warehouse. The main purpose is to gather all information from an organisation into a single repository so that employees can make business decisions and undertake business analysis activities. It allows the organisation to move away from transactional data giving them visibility across the organisation so that reports can written based on the data.
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