CHAPTER 7 : STORING ORGANIZATIONAL INFORMATION - DATABASE

Chapter 7 :Storing Organizational Information - Database

QUESTION FROM THIS CHAPTER:

• Define the fundamental concepts of the relational database model.
• Evaluate the advantages of the relational database model.
• Compare operational 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.

 DEFINE THE FUNDAMENTALS CONCEPTS OF THE RELATIONAL DATABASE MODEL:

  - The relational database model stores information in the form of logically related two-dimensional            tables

 - Entities, attributes, primary keys, and foreign keys are all fundamental concepts included in the             relational database model

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).

• 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.

Hierarchical Structure

Network Structure

Relational Structure

Entities and Attributes

• Entity is a person, place, thing, transaction, or event about which information is stored (The rows in each table contains the entities).

• Attributes is 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.

EVALUATE THE ADVANTAGES OF THE RELATIONAL DATABASE MODEL:

Relational Database Advantages

A) Increased flexibility

A well-designed database should;

• Handle changes quickly and easily
• Provide users with different views
• Have only one physical views
• 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

B) 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

C) 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

D) Increased information integrity (quality)

• Information integrity – measures the quality of information
• Integrity constraint – rules that help ensure the quality of information

COMPARE RELATIONAL INTEGRITY CONSTRAINTS AND BUSINESS-CRITICAL INTEGRITY CONSTRAINTS:

• Relational integrity constraint-rule that enforces basic and fundamental information-based constraints
• Eg. Users cannot create an order for a nonexistent customer ; An order cannot be shipped without an address
• Business-critical integrity constraint-rule that enforce business vital to an organization's success and often require more insight and knowledge than relational integrity constraints.
• Eg. Product returns are not accepted for fresh product for 15 days after purchase

E) Increased information security

• Information is an organization 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

A database management systems (DBMS) is software through which users and application programs interact with a database.

DESCRIBE THE BENEFITS OF DATA DRIVEN WEB SITE:

• A data-driven Web site is 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 are especially useful when the site offers a great deal of information, products, or services. Web site  visitors are frequently, angered if they are buried under an avalanche of information when searching a Web site. A data-driven Web site invites visitors to select and view what they are interested in by inserted a  query, which the Web site then analyzes and custom builds a Web page in real-time that satisfies query.

Data-Driven Websites-A data-driven website is an interactive website keep constantly updated and relevant to the needs of its costumer through the use of a database.

Data-Driven Website Advantages

• Development : Allows the website owner to make changes any time
• Content management : A static website requires a programmer to make updates.
• Future expandability : Having a data-driven website enables the site to grow faster than would be possible with a static site.
• Minimizing human error 
• Cutting production and update costs
• More efficient
• Improved stability

Integrating Information among Multiple Databases

An integration allows separate systems to communicate directly with each other.

DESCRIBE THE TWO PRIMARY METHODS FOR INTEGRATING INFORMATION ACROSS MULTIPLE DATABASES:

• A forward integration takes information entered into a given system and sends it automatically to all downstream processes.
  
  
  

• A backward integration takes information entered into a given systems and sends it automatically to all upstream systems and processes
  
• Building a central repository specifically for integrated information