DATABASES & DATAWAREHOUSES
Weekly Questions – Week Seven
 |
| A visual representation of a database. |
List, describe and provide an example of each of the five characteristics of high quality information.
• Accuracy – all of the values must be correct. For example, a name must be spelt correctly; a dollar amount must be recorded properly.
• Completeness – none of the values should be missing. For example, an address should be complete with a street, city, state and postcode.
• Consistency – arregate or summary information must be in agreement with detailed information. For example, the total fields should be equal to the true total of the individual fields.
• Uniqueness – each transaction, entity and event should appear only once in the information. For example, there should not be any duplicate customers.
• Timeliness – the information should be current to the business requirements. For example, the information should be updated weekly, daily, or hourly.
Define the relationship between a database and a database management system.
Data is raw fats that describe the characteristics of an event, as are the general raw facts used to make up sources of information, or a database. A database maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses). A database management system (DBMS) is used to access information from a database, usually software through which users and application programs interact with the database. The user sends requests to the DBMS and it performs the actual manipulation of the information within the database.
Describe the advantages an organisation can gain by using a database.
- Organisations can accurately store records
- They can distribute information easily
- Implementing databases will reduce redundancy of information
- They will help business processes to be more efficient
- Information integrity – the information stored will be of high quality
- They make sure the information/data is secure by providing authorisation to different groups/departments for the different information that they need.
Define the fundamental concepts of the relational database model.
A relational database model is a type of database that stores information in the form of logically related two-dimensional tables each consisting of rows and columns. The primary concepts of the relational database model are:
• Entities, which is a person, place, thing, transaction or event about which information is stored.
• Entity classes
• Attributes, which are also called fields or columns, are characteristics of properties of an entity or class e.g. the attributes for CUSTOMER may include customer ID, customer name, customer phone etc.
• Keys, where various entity classes are managed and organised once developers identify them as either primary keys (a field that uniquely identifies a given entity in the table which provide a way of distinguishing each entity in a table) or foreign keys (a primary key of one table that appears to be an attribute in another, providing a logical relationship between the two tables.
• Relationships.
Describe the benefits of a data-driven website.
A data-driven website is an interactive website kept constantly updated and relevant to the needs of its customers through the use of a database. They are especially useful when the site offers a great deal of information, products or services as they invite visitors to select and view what they are interested in by inserting a query which is satisfied by a custom built web page, rather than the visitor being inundated or avalanched with information. Websites that contain continually changing information such as press releases, new product information, pricing etc are most suited to having a data-driven website. Some more benefits and advantages of data driven websites include:
• Development, as it allows the website owner to make changes any time, all without having to rely on a developer or knowing HTML programming because a well-structured, data driven website enables updating with little or no training.
• Content management, as a static website requires a programmer to make updates adding an unnecessary layer between the business and its web content, which can lead to misunderstandings and slow turnarounds for desired changes.
• Future expandability, as the site is enabled to grow faster then a static site. Changing the layout, displays, and functionality of the site is easier with a data-driven solution.
• Minimising human error, as well-designed data-driven websites will have ‘error trapping’ mechanisms to ensure that required information is filled out correctly and that content is entered and displayed in its correct format, whereas some highly competent programmers that maintain pages will over look things and therefore make mistakes.
• Cutting production and update costs, as the site can be updated and published by any competent data entry or administrative person, and as well as being convenient and affordable, updating these sites takes a fraction of the time in comparison to static sites.
• More efficient, as the system keeps track of the templates so that users to not have to. Its infrastructure will improve the reliability and stability of a website while greatly reducing the chance of ‘breaking’ a part of the site when adding new areas.
• Improved stability, as the data is never lost compared to that of a static site, where programmers have to keep track of all the source files, and their departure could involve recreating existing work if those source files cannot be found.
No comments:
Post a Comment