Docstoc

DataBase

Document Sample
DataBase Powered By Docstoc
					Database state

Database state is the actual data stored in database at particular moment of time.

Internal schema:-

•       Describes physical storage structure

•       Access paths(indexes)

•       Use physical data model

•       Show low leveldetails

Conceptual schema:-

•       Describes database schema at conceptual level

•       Uses conceptual model

•       Hides low level details

•       Describes database schema for a group of users



External schema

•       Describes database schema at conceptual level

•       Uses conceptual data model

•       Describes database the part of database schema in which a group of users interested.

Data independece




DDL data definition language

Data definition is used to define database schema.
Data manuplation language

Data manuplation language store database schema in database management system catalog.

SDL




VDL




Query language

Query language is used to insert,modify and extract data of database management system.

Host langauge




Database utility

Thes are a set of tools to allow fast and easy data transfer, maintenance, and database administration of
databases.

Catalog

A file that contains the record of table in DBMS and their names etc.

Client/Server architecture

In client server architecture one system act as server and the other ones as client the client requests the
server and the server provides services to their clients.

				
DOCUMENT INFO
Shared By:
Tags: Database, state
Stats:
views:18
posted:10/15/2011
language:English
pages:2