Dbms And Rdbms Tutorial
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,
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
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.....