DBMS and RDBMS

FUNCTION / FACILITIES OF DBMS  ::

Authorization Services :: ensures that only authorized users can access db.

Security Services :: prevents unauthorized users to access db

Integrity Services :: ensures that both the data & changes to db follow certain rules..

Concurrency Control Services:: ensures that db s updated correctly when mutiple

users r updating the db concurently…

Recovery Control sys:: restores the db to a previous consistent state following a

 HW / SW failure…

User Accessable Catalog :: contains descriptions of data items..

data storage, retrievel(query & it's result), updation(del, overwritting, inc, dec)

Data Dictionary : data abt data includes the data which user inputs & the data by

which we defines fields…

Transaction Suuport : which ensures taht either all the updates corresponding to

a given transcation r made or that none of them r made…

Data Communication Support :

Utillities Support : e,g import, export, garbage collection, statistical analysis,

monitoring facilities…

Data Independency :: independence of prog from the actual str of db..

SOFTWARE COMPONENTS OF DM:

                1: Authorization Control

                2: Integrity chacker

                3: Recovery manager

                4: Command Processor

                5: Query Optemizer

                6: Transection Manager

                7: Sheduler

                8: Buffer Manager

 

COMPONENTS OF DBMS:

                1: Query Processor

                2: File Manager

                3: DML Preprocessor

                4: DDL Compiler

                5: Catalog Manager

                6:Data Base Manager

 

DISADVANTAGES OF DBMS::

complex sw :

size :: storage capicity..Ram more (multi user environment)

expensive : as t s complex so it woud be expensive(sw + hw) ,

HW constraints & cost :

Cost Of Conversion :

performance: will be slow becauz of multiuser environment….

Failure /  breakdown…e,g 11sep all data was losed therer was no backup…..