Chapter 7: STORING ORGANIZATIONAL INFORMATION-DATABASES

Relational Database Fundamentals

• Information is everywhere in business.
• Information is stored in databases.

Database – maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses).

• Databases models include :

1. Hierarchical database model: Information is organized into a tree-like structure (using parent/child relationships) in such a way that it cannot have too many relationships.
   
2. Network database model: A flexible way of representing objects and their relationships.
   
3. Relational database model: stores information in the form of logically related two-dimensional tables.
   

Entities and Attributes

Entity  – A person, place, thing, transaction, or event about which information is stored.

• The rows in each table contain the entities. Example in Figure 7.1 CUSTOMER includes Dave’s Sub Shop and Pizza Palace entities.

Attributes (fields, columns) – Characteristics or properties of an entity class.

• The columns in each table contain the attributes such as in Figure 7.1 attributes for CUSTOMER include Customer ID, Customer Name, Contact Name.

Keys and Relationships

Primary keys and foreign keys identify the various entity classes (tables) in the database.

Primary key - A field or group of fields that uniquely identifies a given entity in a table.

Foreign key - A primary key of one table that appears an attribute in another table and acts to provide a logical relationship among the two tables.

• Figure 7.1: Potential relational database for Coca-Cola
  
   

Relational Database Advantages

Database advantages from a business perspective include:

• Increased flexibility.
• Increased scalability and performance.
• Reduced information redundancy.
• Increased information integrity (quality).
• Increased information security.

Increased Flexibility

A well-designed database should:

• Handle changes quickly and easily.
• Provide users with different  views. 
• Have only one physical views.  

 Physical views - Deals with the physical storage of information on a storage device such as hard disk.

• Have multiple logical views.

 Logical views - Focuses on how users logically access information.

• The separation between logical and physical views allows each user to access database information differently.
• Example: A mail to ordering bus - 2 people view different format (logical views) but same physical views. 

Increased Scalability and Performance

• A database must scale to meet increased demand, while maintaining acceptable performance levels.

Scalability -  Refers to how well a system can adapt to increased demands.

Performance - Measures how quickly a system performs a certain process or transaction.

Reduced Information Redundancy

• Databases reduce information.

Redundancy - The duplication of information of information storing the same information in multiple places.

• Inconsistency is one of the primary problems with redundant information. There will be a problem to decide which is most current and most accurate.

Increase information Integrity (Quality)

• Information integrity - Measures the quality of information.
• Integrity constraint - Rules that help ensure the quality of information.
• Relational integrity constraint - Rule that enforces basic and fundamental information-based constraints. For example users cannot create an order for a nonexistent customer, provide a markup percentage that was negative etc.
• Business-critical integrity constraint - Rule that enforce business rule vital to an organization's success and often require more insight and knowledge than relational integrity constraints. Example product returns are not accepted for fresh product 15 days after purchase.

Increased Information Security

Information is an organizational asset and must be protected. Databases offer several security features including:

• Password - Provides authentication of the user.
• Access level - Determines who has access to the different types of information.
• Access control - Determines types of user access, such as read-only access.

Database Management System (DBMS)

Database management system (DBMS) - Software through which users and application programs interact with a database. 

 

Indirect Interaction

• User interacts with an application for example payroll application, manufacturing application, sales application.
• The application interacts with the DBMS.
• The DBMS obtains the information from the database.

Direct Interaction

• The user interacts directly with the DBMS.
• The DBMS obtains the information from the database.

Data-driven Websites

Data-driven Websites - An interactive website kept constantly updated and relevant to the needs of its customers through the use of a database.

• Data-driven Web sites are especially useful when the site offers a great deal of information, products, or services.
• A data-driven Web site invites visitors to select and view what they are interested in by inserting a query, which the Web site then analyzes and custom builds a Web page in real-time that satisfies the query.

 

Data-Driven Website Business Advantages

• Development : Allows the website owner to make changes any time-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.
• Content management : A static website requires a programmer to make updates. This adds an unnecessary layer between the business and its web content, which can lead to misunderstandings and slow turnarounds for desired changes.
• Future expandability : Having a data-driven Web site enables the site to grow faster than would be possible with a static site.  Changing the layout, displays, and functionality of the site (adding more features and sections) is easier with a data-driven solution.
• Minimizing human error : Even the most competent programmer charged with the task 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 displayed 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 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 minutes.
• 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.
• 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.

Data-Driven Business Intelligence

• Bi in a data-driven website.
• Companies can gain BI by viewing the data accessed and analyzed from their Web site.  The figure displays how running queries or using analytical tools, such as a Pivot Table, on the database that is attached to the Web site can offer insight into the business, such as items browsed, frequent requests, items bought together, etc.

 

Integrating Information among Multiple Databases 

Integration - Allows separate systems to communicate directly with each other.

 Without integration, an organization will:

• Spend considerable time entering the same info in multiple system.
• Suffer from the low quality and inconsistency typically embedded in redundant info.

An organization can choose from two integration methods.

1. Forward and backward integrations that link processes in the value chain.
2. Central repository for a particular type of information.

Forward Integration 

Forward integration - Takes information entered into a given system and sends it automatically to all downstream systems and processes.

• Sales enters the information when it is negotiating the sale (looking for opportunities).
• The information is then passed to the order entry system when the order is actually placed.
• The order fulfillment system picks the products from the warehouse, packs the products, labels boxes, etc.
• Once the order is filled and shipped, the customer is billed.

Backward Integration

Backward integration - Takes information entered into a given system and sends it automatically to all upstream systems and processes.

• Billing enters information and this information is passed back to the order system.
• The order fulfillment system passes the information back to the order entry system.
• The order entry system passes the information back to the sales system.

Central Repository

 Building a central repository specifically for integrated information.

• The above figure displays an example of customer information integrated using this method.
• Users can create, read, update, and delete in the main customer repository, and it is automatically sent to all of the other databases.
• This method does not follow the business process when building the integrations.
• Business-critical integrity constraints still need to be built to ensure information is only ever entered into the customer repository, otherwise the information will become out-of-syn.