Wednesday, September 16, 2015

Chapter 7 : Storing Organizational Information

Relational Database Fundamentals :

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

Entities and Attributes :

=> A person, place, thing, transaction or event about which information is stored.

=> Characteristics or properties of an entity class.

Keys and Relationships :

  • 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 that appears an attribute in another table and acts to provide a logical relationship among the two tables.  

Relational Database Advantages :
  • Increased flexibility.                                                                  
Physical view - deals with the physical storage of information on a storage device.
Logical view - focuses on how users logically access information. 
  • Increased scalability and performance.
Scalability - refers to how well a system can adapt to increased demand.
Performance - measures how quickly a systems performs a certain process or transaction.
  • Reduced information redundancy.
Redundancy - the duplication of information or storing the same information in multiple places. \
  • Increase information integrity ( quality ).
Information integrity - measures the quality of information. 
Integrity constraint - rules that help ensure the quality of information. 
  • Increased information security.
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.

Data-Driven Website Business 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 systems 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.

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