CHAPTER 7 : STORING ORGANIZATIONAL 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).

• Database models include :

1. 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.
2. Network database model - a flexible way of representing objects and their relationships.
3. Relational database model - stores information in the form of logically related two-dimensional tables.

ENTITIES & ATTRIBUTES

* Entity - a person, place, thing, transaction, or event about  which information is stored

• The rows in each table contain the entities
• In Figure 7.1 CUSTOMER includes Dave's Sub Shop and Pizza Palace entities

*Attributes (fields,columns) - characteristics or properties of an entity class

• The columns in each table contain the attributes.
• In Figure 7.1 attributes for CUSTOMER include Customer ID, Customer Name, Contact Name

KEYS & 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 identity 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.

Potential relational database for Coca-Cola

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

                *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

INCREASED SCALABILITY & 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 - measure how quickly a system performs a certain process of 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.

INCREASED 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 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 a 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 INTELLIGENCE 

• BI in a data-driven Web site

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.