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:

1. Development
2. Content management 
3. Future expandability
4. 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.