CHAPTER 7 - STORING ORGANIZATIONAL INFORMATION-DATABASE

Relational database fundamentals

1.Database - maintains information about various types of object (inventory), events (transactions), people (employees), and place (ware-house).

2.Hierarchical database mode - information organized into tree-like structure that allows repeating information using parent/child relationships in such a way that it cannot have too many relationships.

3.Network database model - Is a flexible way of representing objects and their relationships.

4.Relational database model - Stores information in the form of logically related two-dimensional tables.

Entities and Attributes

Entity – person, place, thing, transaction, or event about which information is stored.

Attributes – fields or columns are characteristics or properties of an entity class.

                            

                              

Keys and Relationships

Primary key - is a field that uniquely identifies a given entity in a table.

Foreign key - in the relational database model is primary key of one table that appears between as an attribute in another table and acts to provide logical relationship between the two tables.

Relational database advantages

• increased flexibility 

physical view- information deals with the physical storage of information on a storage device such as hard disk. 
logical view- information focus on how users logically access information to meet their particular business needs.

• increased scalability and performance 

scalability- how well a system can adapt to increased demands.
performance- measures on how quickly a system performs a certain process or transaction.

• reduced information redundancy 

redundancy- duplication of information , or storing the same information in multiple places.

• increased information integrity 

information integrity- measure of quality of information
integrity constraints- rules that help ensure the quality information. 

1. rational integrity constraints 
2. business-critical integrity constraints 

relational integrity constraints- rules that enforce basic and fundamentals 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.

• increased information security 

including passwords, access levels, and access control.

Database management systems

Database management systems(DBMS)- software through which usrs and application programs interact with a database.

Data-driven websites

             

 " is an interactive website kept constantly update and relevant to the needs of its customers through the use of a database"

Data-driven website business advantages :

• development 
• content management 
• future expandability 
• minimizing human errors 
• cutting production and update costs. 
• more efficiently 
• improved stability 

Integrating information among multiple database

• Integration - allows separate systems to communicate directly with each other.
• Forward integration - takes information entered into a given systems and sends it automatically to all downstream systems and processes.
• Backward integration - takes information entered into a given systems and sends it automatically to all upstream systems ans processes.