CHAPTER 7 : STORING ORGANIZATIONAL INFORMATION DATABASES

RELATIONAL DATABASE FUNDAMENTALS

Database > maintains information about various type of objects (inventory),event (transaction), people (employees) and place (ware houses).

Hierarchical > information is organized into a tree like structure that allows repeating information using parent or child relationship in such a way that it cannot have too many relationship.

Network Database Model > flexible way of representing object and their relationship.

Relational Database model > type of database that store  information in the form of logically related two dimensional tables.This is focus on the relationship database model.

ENTITIES AND ATTRIBUTES

Entity

The relationship database model is :

• person
• place 
• thing
• transaction
• event 

ATTRIBUTES

Called fields or columns are characteristic or properties of an entity class.


KEYS AND RELATIONSHIPS

Primary key : is a field or group of fields that uniquely identifies a given entity in a table. Primary keys are important because they provide a way of distinguishing each entity in a table.

Foreign key : The relationship database model is a primary key of one table that appears as an attribute in other table and acts to provide a logical relationship between the two tables.
 
RELATIONAL DATABASE ADVANTAGES

1) Increase Flexibility

• the physical view of information deals with the physical storage of information on a storage device such as a hard disk.
• The logical view of information focuses oh how users logically access information to meet their particular business need.

2) Increase Salability and Prformance

• Scalability refers to how well a system can adapt to increased demands.
• Performance measures how quickly a system performs a certain process or transaction.

3) Reduced Information Redundancy

• Redundancy id the duplication of information or storing the same information in multiple place.

4) Increased Information Integrity (Quality)

• Information integrity is a measure of the quality of information 
• Integrity constraints are rules that help ensure the quality of information.
• Relational integrity constraints are rules that enforce basic and fundamental information based constraints.
• Business critical integrity constraints enforce business rule vital to an organization success and often require more insight and knowledge than relational integrity constraints.

5) Increase Information Security

• Information is an organizational asset and must be protected.
• Databases offer several security features including :
• Password
• Access Level
• Access Control

DATABASE MANAGEMENT SYSTEMS

DBMS > Software through which users and application programs interact with a database.

Data Driven Web Site >  an interactive Web site kept constantly update and relevant to the needs of its customers through the use of a database.

Data  Driven Site Business Advantage 

• Development 
• Content Management 
• Future Expandability
• Minimizing Human Error
• Cutting Product and Update Costs
• More Efficient
• Improved Stability