CHAPTER SEVEN - STORING ORGANIZATIONAL INFORMATION-DATABASE

Rational Database Fundamentals

Database maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouse).

Hierarchical Database Model – information is organized into a tree-like structure that allows repeating information using parent/child relationship such a way that it cannot have too many relationships.

Network Database Model – flexible way of representing objects and their relationships.

Relational Database model – type of database that stores information in the form of logically related two-dimensional tables.

ENTITIES AND ATTRIBUTES

An entity in the relational database model is a person, place, thing, transaction, or event about which information is stored.

A table in relational database model is a collection of similar entities.

Attributes also called column or fields, are characteristics or properties of an entity class.

KEYS AND RELATIONSHIPS

A primary key is a field (or group of fields) that uniquely identifies a given entity in a table.

The primary keys are important because they provide a way of distinguish each entity in a table.

A foreign key in the relational database model is a primary key of one table that appears as an attribute in another table and acts to provide a logical relationships between the to tables.

Relational Database Advantages

From a business perspective, database information offers many advantages, including :

INCREASE FLEXIBILITY

Handle changes quickly and easily.

Provide users with different views.

Have only one physical view.

The physical view of information deals with the physical storage of information on a storage device such as hard disk.

Have multiple logical views.

The logical view of information focuses on how user logically access information to meet their particular business needs.

INCREASE SCALABILITY AND PERFORMANCE

Only a database could “scale” to handle the massive volumes of information and the large number of users required for the successful.

Scalability refers to how well a system can adapt to increased demands.

Performance measures how quickly the system performs a certain process or transaction.

REDUCE INFORMATION REDUNDANCY

Redundancy is the duplication of information, or storing the same information in multiple places.

The primary problem with redundant information is that it is often inconsistent, which makes it difficult to determine which values are the most current or most accurate.

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 System

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

The user sends requests to the DBMS and the DBMS performs the actual manipulation of the information in the database.

Two ways that users can interact with DBMS : (1) Directly and (2)  indirectly.

Interacting Directly and Indirectly with a Database through a DBMS

DATA-DRIVEN WEBSITES

The pages on website must change according to what a site visitor is interested to browsing.

A data-driven website is an interactive website kept constantly updated and relevant to the needs of customers through the use of a database.

Wikipedia - Data-Driven Website

Data-Driven Website Advantages

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.

 A Forward and Backward Customer Information Integration Example

Building a central repository specifically for integrated information.

User can create, update, and delete customer information only in the central customer information database.

Integrating Customer Information among Database