Friday, July 19, 2013

Chapter 7 - Storing Organizational Information - Database


RELATIONAL DATABASE FUNDAMENTALS

 -    Information is everywhere in an organization
-  Information is stored in databases
Ø   Database – maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses)
 -     Database models include;
Ø   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.



         Ø  Network database model – a flexible way of representing objects and their relationships


        Ø  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
Ø  The rows in each table contains the entities

-    Attributes (fields, columns) – characteristics or properties of an entity class
Ø  The columns in each table contain the attributes

KEYS AND RELATIONSHIPS

-    Primary keys and foreign keys identity the various entity classes (tables) in the database
Ø  Primary key – a fields (or group of fields) that uniquely identities a given entity in a table
Ø  Foreign key – a primary key of one table that appears an attribute in another table and acts to provide a logical relationships among the two tables 


RELATIONAL DATABASE ADVANTAGES

-    Database advantages from a business perspective include;
Ø  Increased flexibility
Ø  Increased scalability and performance
Ø  Reduced information redundancy
Ø  Increased information integrity (quality)
Ø  Increased information security

INCREASED FLEXIBILITY

-     A well-designed database should;
Ø  Handle changes quickly and easily
Ø  Provide users with different views
Ø  Have only one physical views
§  Physical view – deals with the physical storage of information on a storage device
Ø  Have multiple logical views
§  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
Ø  Scalability – refers to how well a system can adapt to increased demands
Ø  Performance – measures how quickly a system performs a certain process or transaction

REDUCED INFORMATION REDUNDANCY

-      Databases reduce information redundancy
Ø  Redundancy – the duplication of information or storing the same information in multiple places
-     Inconsistency is one of the primary problems with redundant information

INCREASED INFORMATION SECURITY

-      Information is an organization asset and must be protected
-      Databases offer several security features including;
Ø  Password – provides authentication of the user
Ø  Access level – determines who has access to the different types of information
Ø  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 WEB SITES

-       Data-driven Web sites – an interactive Web site kept constantly updated and relevant to the needs of its   customers through the use of database


DATA-DRIVEN WEB SITE BUSINESS ADVANTAGES

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

DATA-DRIVEN BUSINESS INTELLIGENT

-         BI in a data-driven Web site


INTEGRATING INFORMATION AMONG MULTIPLE DATABASES

-      Integration – allows separate systems to communicate directly with each other
Ø  Forward integration – takes information entered into a given system and sends it automatically to all downstream systems and processes





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

 -          Building a central repository specifically for integrated information

Question?

1.       Define the fundamental concepts of the relational database model
2.       Evaluate the advantages of the relational database model
3.       Compare relational integrity constraints and business critical integrity constraint
4.       Describe the benefits of a data driven Web site
5.       Describe the two primary methods for integrating information across multiple database

No comments :

Post a Comment