Thursday, 19 May 2011

Database Chapter 3, Revision for final exam :)


Database is a collection of information that you organize and access according to a logical structureof that information.

Relational Database

Uses series of logically related two dimensional tables or files to store information in form of database.
 logical structure creates an integrity constrains which means that a two related table of information with relation to each other is complete make sense and reliable, thus it doesn't make wrong of ones data stored.

Database Management System Tools

1. DBMS engine
2. Data definition subsystem
3. Data manipulating subsystem
4. Application generation subsystem
5. Data administration subsystem

DBMS engine - accepts logical request from the various other DBMS subsystem, converts them into their physical equivalent, and actually accesses the database and data dictionary as they exist on a storage device. which mean, all data from the data subsystem is transferred and gathered in DBMS and converted into a logical data that easily been interpreted by data users.

Data subsystem

Data definition - helps you create and maintain the data dictionary and define the structure of the files in a database

Data manipulation - helps you add, change, and delete information in data system and query it for valuable information

Application generation - contains facility to help you develop transaction-intensive applications.

Data administration - helps you manage the overall database information by providing facilities for backup and recover, security management, query optimization, concurrency control, and change management. usually used by administrative users.

Data warehouse

Data warehouse is commonly same as database engine but data warehouse gathered information from many different operational database from every task or department.

taken from ; Mcgraw - hill, MIS 8th edition

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