NOTE IT CHAPTER 7 STORING ORGANIZATIONAL INFORMATION DATABASE  

relation database information	•Information is everywhere in an organization •Information is stored in databases -Database - maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses)
relational database information	Database models include: Hierarchical database model, Network database model, Relational database model
Hierarchical database model	information is organized into a tree-like structure (using parent/child relationships) in such a way that it cannot have too many relationships
Network database model	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 -The rows in each table contain the entities -In Figure 7.1 CUSTOMER includes Dave's Sub Shop and Pizza Palace entities
Attributes (fields, columns)	characteristics or properties of an entity class -The columns in each table contain the attributes -In Figure 7.1 attributes for CUSTOMER include Customer ID, Customer Name, Contact Name
Keys and Relationships	Primary keys and foreign keys identify the various entity classes (tables) in the database
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 advantage	Database advantages from a business perspective include -Increased flexibility -Increased scalability and performance -Reduced information redundancy -Increased information integrity (quality) -Increased information security
Increased Flexibility	A well-designed database should: -Handle changes quickly and easily -Provide users with different views -Have only one physical view
Physical view	- deals with the physical storage of information on a storage device -Have multiple logical views
Logical view	focuses on how users logically access information
Increased Scalability and Performance	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 or transaction
Reduced Information Redundancy	Databases reduce information redundancy
Redundancy	•the duplication of information or storing the same information in multiple places •Inconsistency is one of the primary problems with redundant information
Increase Information Integrity (Quality)	•Information integrity - measures the quality of information •Integrity constraint - rules that help ensure the quality of information -Relational integrity constraint -Business-critical integrity constraint
Increased Information Security	Information is an organizational asset and must be protected
Databases offer several security features including:	-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
Database management systems	Database management systems (DBMS) - software through which users and application programs interact with a database
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
Integrating Information among Multiple Databases	Forward integration and backward integration
Integrating Information among Multiple Databases	Building a central repository specifically for integrated information