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Saturday, 12 September 2015



- Information is stored in database.

 Relational Database Fundamentals
 - Database : maintain information about various types of objects (inventory), events (transaction),        people(employees), and     places(warehouses).
 - Hierarchical database model : information is organised into a tree-like structure that allows repeating using parent/child                 relationship.
 - Network database model : a flexible way of representing objects and their relationship.
- Relational database model : type of database that stores information in the form of logically related two-dimensional tables.

 Entities And Attributes 

 - Entity : is a person, place, thing, transaction, or event about which information is stored.
- Attributes : is fields or columns, are characteristics or properties of an entity class.

 Relational Database Advantages 

- Increased flexibility
 : a good database and any good business must able to handle changes quickly and easily.
 : physical view – information deals with physical storage of information on a storage device.
: logical view – information focuses on how users logically access information to meet their particular business needs.

 - Increased scalability and performance
: scalability – refers to how well a system can adapt to increased demand.
: performance – measures how quickly a system performs a certain process or transaction.
: database today scale to exceptional levels, allowing all types of users and programs to perform information-processing and information-searching tasks.

 - Reduced information redundancy
 :redundancy – is the duplication of information or storing the same information in multiple places.
 :database is to eliminate information redundancy

 - Increased information and integrity (quality)
 : information integrity – measure of the quality of information : information constraints – rules that help ensure the quality of information
: relational integrity constraints – rules that enforce basic and fundamental information-based constraints. :business-critical integrity constraints – enforce business rules vital to an organization’s success and often requires more insight and knowledge.

 - Increased information security : information is an organizational asset. : passwords provide authentication of the user who is gaining access to the system.
 : Access levels determine who has access to the different types of information.
 : Access controls determine what types of access they have to the information.

 Database Management System 
 - Database management system (DBMS) : is a software through which users and application programmes interact with the database.

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