Tuesday, 18 August 2015

Lets Collaborateee with Information !

Chapter 7 - Information

What is Information?

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)

Relational Database Fundamentals

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
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
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

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
Have multiple logical views
Logical view – focuses on how users logically access information 

Increased Scalability and Performances

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
Redundancy – the duplication of information or storing the same information in multiple places 

Inconsistency is one of the primary problems with redundant information

Increase Information Integrity

Information integrity – measures the quality of information

Integrity constraint – rules that help ensure the quality of information
Relational integrity constraint
Business-critical integrity constraint 

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

Database management systems (DBMS) – software through which users and application programs interact with a database

Data Driven Websites

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 Website Business Advantages

Content Management
Future Expandability
Minimizing Human Error
Cutting Production and Update Costs
More Efficient
Improved Stability

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 to all downstream systems and processes
Backward integration – takes information entered into a given system and sends it automatically to all upstream systems and processes


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