Monday, 29 February 2016

THE MAKING OF CHAPTER 7

STORING ORGANIZATIONAL INFORMATION—DATABASES


 What is INFORMATION?


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)

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
·         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 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
Ø  Physical view – deals with the physical storage of information on a storage device
·         Have multiple logical views
Ø  Logical view – focuses on how users logically access information

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
·         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 (Quality)
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 SYSTEMS
Database management systems (DBMS) – software through which users and application programs interact with a 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 WEBSITE 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 website


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

INTEGRATING INFORMATION AMONG MULTIPLE DATABASES
Forward integration and backward integration


INTEGRATING INFORMATION AMONG MULTIPLE DATABASES
Building a central repository specifically for integrated information


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