CHAPTER 7: Storing Organizational Information-Databases

  CHAPTER 7: Storing Organizational Information-Databases

• Database- maintains information about various types of object, event , inventory, people and
  place. 
• Hierarchical database model-information is organized into a tree-like structure 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. 
• Entity- a person, place, thing or event about which information is stored. 
• Attributes- characteristics or properties of an entity class. 
• Primary key- a field 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 two tables. 
• Relational database advantages:
  -Increased flexibility
  -Increased scalability and performance
  -Reduced information redundancy.
  -Increased information integrity
  -Increased information security.

1. Increased flexibility
Handle changes quickly and easily, provide users with the different views, have only one view, have mutiple logical views.

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.

2 . Reduced information redundancy
Redundancy-the duplication of information or storing the same information in multiple place.

3. Increased information integrity:

-Information integrity-measures the quality of information.
-Integrity constraint-rules that help ensure the quality of information.

4. Increased information security
- information is an organization asset and must be protected.

Database features:

1. password-provides authentication of the user.
2. access level-determines who has access to the different types of information.
3. access control -determines types of user access.

• Database management systems-software through which users and application programs interact with a database. 
• Data-driven web sites-an interactive web site kept constantly updated and relevant to the needs of its customers through the use of database. 
• advantages:
  - Development
  -Content management
  - Future expandability
  - More efficient 

Integrating Information among Multiple Database.

1. Forward integration-takes information entered into a given system and sends it automatically to all downstream system process. 
2. Backward integration-takes information entered into a given system and sends it automatically to all upstream systems and process.
3. without integration, an organization will spend considerable time entering the same info in multiple system.