Friday, 20 September 2013

CHAPTER 7: STORING ORGANIZATIONAL 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)
•          Database models include:
–      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 – a flexible way of representing objects and their relationships
–      Relational database model – stores information in the form of logically related two-dimensional tables

ENTITY AND ATTRIBUTES
•          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

KEY 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 ADVANTAGES
•          Database advantages from a business perspective include
–      Increased flexibility
–      Increased scalability and performance
–      Reduced information redundancy
–      Increased information integrity (quality)
–      Increased information security

•          Database management systems (DBMS) – 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 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




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