• Accuracy-relates the information and whether it is correct, for example is the name spelt correctly or has the date been recorded correctly.
• Completeness- whether all the required information is there or is there values missing. When recording the address of a customer is all necessary elements included such as the number, street, suburb and postcode.
• Consistency-is the information in agreement in all areas such as the total field of the information equal to all the individual fields.
• Uniqueness-is each transaction, entity and event represented only once in the information. Has any single customer been entered into the database more than once?
• Timeliness the information up-to-date with the needs of the business. How often is the information updated such as hourly, weekly, monthly in terms of addressing the requirements of the business.
Define the relationship between a database and a database management system.
• A database maintains information about various types of objects, events, people and places; it has a schema which is a structural description of the types of information held within the database. A database management system is a computer program designed to manage and query a database. It is a program through which users are able to interact with the database. The user sends request to the database management system which in turn performs the manipulation of the database to gain the required information. The relationship is one of which the database management system acts to obtain or seek out information within the database through queries.
- follow this link for information on Database Management Systems and how a database improves the quality of information
There is many advantages to a good database such as flexibility, increased scalability and performance, reduced information redundancy, increased information integrity and increased information security.
A database allows the flexibility of allowing any user to access the information in whichever way suits there required needs. Consider the example that one user might require the customer records in alphabetical format in which case the surname should appear first where as another user might require the same records working with a catalogue mailing system in which case they require the first name to come first. A database allows flexibility in how the information is stored and viewed. A good database is also able to handle changes quickly and easily just as any business needs to handle changes in the same way and thus a database is able to support an organisation in this regard.
Scalability refers to the ability to cope with increased demand, an organisation must be able to support hundreds of thousands of online users including employees, partners, customers and suppliers. Databases are able to scale to exceptional levels to support all users and programs to perform information processing and searching tasks.
A database is able to reduce information redundancy which is the duplication of information, this occurs because organisations constantly store the same information in multiple locations. The problem with redundant information occurs when it is recorded inconsistently, thus leaving it difficult to determine which values are correct and most accurate. One goal of a database is to eliminate incorrect information by recording information in only one place in the database; this saves space, makes performing information updates easier and improves the quality of the information.
The integrity of the information refers to the quality, in a database integrity constraints ensure the quality of information is high. The database management system ensures that users are unable to violate the two constraints, relational integrity constraints and business-critical integrity constraints. Relational integrity constraints are the rules that enforce basic and fundamental information based constraints such as placing an order for a nonexistent customer. Business-critcal constraints enforce business rules that are required in order for the database to improve the success of the business, these require knowledge and insight. The integrity constraints are responsible for better quality information which in turn produces better quality decisions.
Any organisation must protect its information which is an asset; a database offers many security features such as passwords, access levels and access controls. Therefore a data base not only stores the information but can be responsible for the security of the information.
Define the fundamental concepts of the relational database model.
The fundamental concepts of the relational database model are the entities, entity classes, attributes, keys and relationships. An entity is the person, place, thing transaction or event that the database describes or of the information stored. The attributes, the columns or fields are characteristics of the entity class which if describing a customer may include Customer ID, Customer Name and Phone. The two keys the primary key and the foreign key are used to establish the relationships with the database. The primary key is field that identifies an entity in a table and a foreign key is the primary key in one table that also appears as the attribute in another table. The foreign keys act to provide a relationship between both the tables.
Describe the benefits of a data-driven website.
A data driven website is one which is kept constantly updated to the requirements of the customers by an integrated database. With any website there may be a large quantity of information which a majority proves useless for a particular user, on a data-driven website the user is able to apply a query to return on the information specific to their interests.
A data-driven website can be updated frequently with little difficulty, no developer or HTML programming are required. The website can grow and change faster than a typical static website, small changes such as the layout, displays and functionality of the site are easier, A well designed data driven website will have ‘error trapping’ to ensure that the information in entered in the correct format and filled out correctly, which can be a difficult taks with large amounts of content. Most static websites require a programmer which means that a business does not have direct access to the site which delays any changes and can cause misunderstandings.
Describe the roles and purposes of data warehouses and data marts in an organization
A data warehouse is a collection of databases that supports business activities and decision making. The data warehouse fulfills the role of bringing all the information of the databases into a central location to allow employees to make decisions and undertake business analysis. The data warehouse brings together the same information in aggregated form to simplify the activities.
A data mart brings together the information in a subset to focus on a particular unit within the business. With a given unit the data mart provides the specific information such as that related to finance. This provides a more efficient process of decision making and analysis within a given area, without the need to sort out the unnecessary information in the database.
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