Storing Organizational Information - Database

Storing Organizational Information - Database

CHAPTER 7

The computer program used to manage and query database is known as a database management system (DBMS) 

Relational Database Fundamentals 

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 RELATIONSHIP

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 tables
• 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 Advantage

i) Increased Flexibility

 A good database can handle changes quickly and easily

Physical view - deals with the physical storage of information on a storage device such as hard disk
Logical View - information focuses on how users logically access information to meet their particular business needs

This separation of logical and physical views is what allows each user to access 
database information differently

ii) 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 system performs a certain process or transaction  

iii) Reduced Information Redundancy

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

Eliminating information redundancy saves space, makes performing information update easier, improves information quality.

iv) Increased Information Integrity ( Quality)

Information Integrity - is a measure of the quality of information.

Integrity Constraints - rules that help ensure the quality of information

 > Relational Integrity Constraints
Rules that enforce basic and fundamental information- based constraints

> Business - Critical Integrity Constraints
Enforce business rules vital to an organization's success and often require more insight and knowledge than relational integrity constraints 

v) Increased Information Security 
Databases offer many security features including passwords, access levels and access controls.

Database Management Systems 
DBMS - is software through which users and application programs interact with a database

DATA DRIVEN WEBSITES

Interacting Directly  and Indirectly with a Database through a DBMS

Is an interactive website kept constantly updated and relevant to the needs of its customers through the use of a database. For example Wikipedia, social network.
Data driven website invites visitors to select and view what they are interested in by inserting a query.

Wikipedia - Data Driven Website

Data Driven Website Advantage 

* Development : Allows the website owner to make change anytime.

* Content Management : A static website requires programmer to make updates. 

* 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.

Data Driven Business Intelligence

BI in a DDW

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 system an processes

A forward and backward customer information integration

Integrating Customer Information among Databases