CHAPTER 7

STORING ORGANIZATIONAL INFORMATION - DATABASES

In this chapter, we learned about :

• Define the fundamental concepts of the relational database model
• Evaluate the advantages of the relational database model
• Compare relational integrity constraints and business-critical integrity constraints
• Describe the benefits of a data driven Web site
• Describe the two primary methods for integrating information across multiple databases

RELATIONAL DATABASE FUNDAMENTALS

• Information is everywhere in an organization
• Information is stored in databases

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

• Database models include :

- 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

- Network database model : a flexible way of representing objects and their relationships

- 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

• Attributes (fields, columns) : characteristics or properties of an entity class

- the columns in each table contain the attributes

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 and attribute in another table and acts to provide a logical relationship among the two tables

• 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 view

• physical view : deals with the physical storage of information on a storage device. For example, hard disk

- have multiple logical views

• logical view : focuses on how users logically access information

- example : a mail-order bus - two people view different format (logical views) but same physical view

INCREASED SCALABILITY AND PERFORMANCE

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

- 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

- redundancy : the duplication of information or storing the same information in multiple places

• Inconsistency is one of the primary problems with redundant information difficult to decide which is most current and most accurate

INCREASED 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

- Example : users cannot create an order for a nonexistent customer, provide a markup percentage that was negative

- business-critical integrity constraint : rule that enforce business rules 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 : provide 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 SYSTEMS

• Database Management Systems (DBMS) : software through which users and application programs interact with a database

DATA-DRIVEN WEB SITES

• Data-driven web sites : an interactive Web site kept constantly updated and relevant to the needs of its customers through the use of a database

DATA-DRIVEN WEB SITE BUSINESS ADVANTAGES

• Development
• Content management
• Future expandability
• Minimizing human error
• Cutting production and update costs
• More efficient
• Improved stability

DATA-DRIVEN BUSINESS INTELLIGENCE

• BI in a data-driven Web site

INTEGRATING INFORMATION AMONG MULTIPLE DATABASES

• Integration : allows separate systems to communicate directly with each other

- forward integration : takes information entered into a given system and sends it automatically downstream systems and processes

- backward integration : takes information entered into a given system and sends it automatically to all upstream systems and processes

• Forward integration 

• Backward integration

• Building a central repository specifically for integrated information
  
  
  
• 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 information