Chapter 7: Storing Organizational Information- Databases

Relational Database Fundamentals
Database- Maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses).

 Database models include:

• Hierarchical database model- information is organized into a tree-like structure in such a way that it cannot have too many reltionships.
• 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, transaction or event about which information is stored.
Attributes- characteristics or properties of an entity class.

Primary key- a field(or group of fields) that uniquely identifies a given entity in a table
Foreign key- a primary key of one table and acts to provide a logical relationship among the two tables.


Database advantages from a business perspective:

• Increased flexibility
• Increased scalability and performance
• Reduced information redundancy
• Increased information integrity (quality)
• Increased information security

A well designed database should:

• Handle changes quickly and easily
• Provide users with different view
• Have only one physical view- deals with the physical storage of information on a storage device
• Have multiple logical views- focuses on how users logically access information. 

A database must scale to meet increased demand, while maintaining acceptable performance kevels:

• Scalability- refers to how well a system can adapt to increased demands
• Performance- measures how quickly a system performs a certain process or transaction

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.


Advantages:

• Development
• Content management
• Future expandability
•  Minimizing human error
• Cutting production and update costs
• More efficient
• Improved stability

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.