Sunday, 27 September 2015


               -Information is stored in databases
 Database is maintain information about various type of object, events, people, and places

-Database model

Hierarchical database :
 information is organized into a tree-like structure in such away that it cannot have too many relationships

Network database:
a flexible way of representing object and their relationships

Relational database model:
stores information in the form of logically related two-dimensional tables

a person, place, thing, transaction or event about which information is stored
characteristics or properties of any entity class

-Primary key
a field that uniquely identifies a given entity in a table
-Foreign key 
a primary key of one table taht appears an attribute in another table acts to provide a logical relationship among the two table

-Advantages relational database
:increased flexibility
Physical view
logical view

:increased scalability and performance

:reduced information redundancy

:increased information integrity
information integrity
integrity constraint

:increased information security
access level
access control

-Database management systems
software through which users and application programs interact with a database

-Data-driven web sites
an interactive web site kept constanly updated and relevant to the needs ot its customers through the use of a database

: development
:content management
:future expandabilit
:minimizing human error
:cutting production and update costs
:more efficient
:improved stability

-Inteligrating information among multiple databases

forward integration
backward integration

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