CHAPTER 7 : STORING ORGANIZATIONAL INFORMATION – DATABASES

LEARNING OUTCOMES

7.1 Define the fundamental concepts of the relational database model

The relational database model is a type of database that stores information in the form of logically related two-dimensional tables. For an example, web sites of student portal UiTM, when student click to student portal, then click to subjects, inside it have all the subjects that student taken. In the primary concepts of the relational database model have an 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. Attributes also called fields or columns, are characteristics or properties of an entity class. Developers must identify primary keys and foreign keys in order to manage and organize various entity classes within the relational database model and use both of keys to create logical relationships. A primary key is a field (or group of fields) that uniquely identifies a given entity in a table. It are important because they provide a way of distinguishing each entity in a table. A foreign key in the relational database model is a primary key of one table that appears as an attribute in another table and acts to provide a logical relationship between the two tables.

7.2 Evaluate the advantages of the relational database model

The advantages of the relational database model are :

Ø  Increased flexibility – database provide flexibility in allowing each user to access the information in whatever way best suits his or her needs.  The distinction between logical and physical views is important in understanding flexible database user views.

Ø  Increased scalability and performance – only a database could ‘scale’ to handle the massive volumes of information and the large numbers of users required. Scalability refers to how well a system can adapt to increased demands. Performance measures how quickly a system performs a certain process or transaction.

Ø  Reduced information redundancy – is the duplication of information or storing the same information in multiple places. Redundant information occurs because organizations frequently capture and store the same information in multiple locations.

Ø  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.

Ø  Increased information security – as systems become increasingly complex and more available over the Internet, security becomes an even bigger issue.

7.3 Compare relational integrity constraints and business-critical integrity constraints.

There are two types of integrity constraints :

Relational integrity constraints

Business-critical integrity constraints

Rules that enforce basic and fundamental information-based constraints. For an example, an operational integrity constraint would not allow someone to create an order for a nonexistent customer, provide a markup percentage that was negative or order zero pounds of raw materials from a supplier.

Enforce business rules vital to an organization’s success and often require more insight and knowledge than relational integrity constraints. Consider a supplier of fresh produce to large grocery chains. The supplier might implement a business-critical integrity constraint stating that no product returns are accepted after 15 days past delivery. That would make sense because of the chance of spoilage of the produce.

7.4 Describe the benefits of a data-driven website

Advantages of a data-driven website :

ü  Development – allows the website owner to make changes any time and all without having to rely on a developer or knowing HTML programming. A well-structured data-driven website enables updating with little or no training.

ü  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 with a static site. While training a competent programmer can take months or even years, training a data-entry person can be done in 30-60 minutes.

ü  More efficient – by their very nature, computers are excellent at keeping volumes 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 programmed 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 stability of a website, while greatly reducing the chance of ‘breaking’ some part of the site when adding new areas.

ü  Improved stability – any programmer who has to update a website from ‘static’ templates must be very organized to keep track of all the source files. If a programmer leaves unexpectedly, it could involve re-creating existing work if those source files cannot be found. Plus, if there were any changes to the templates, the new programmer must be careful to use only the latest version. With a data-driven website, there is peace of mind, knowing the content is never lost even if your programmer is.

7.4 Describe the two primary methods for integrating information across multiple databases 

An organization can choose from two integration methods which are forward and backward integration.....

Forward integration takes information entered into a given system and sends it automatically to all downstream systems and processes. Means the expansion of a business products or services to related areas in order to more directly to fulfill the customer's needs. An example, farmers sell his or her crops at the local market rather than to a distribution center...
Backward integration takes information entered into a given system and sends it automatically to all upstream systems and processes..