IMPORTANT QUESTIONS FOR IBPS IT SO AND Also Gate exam

Data Independence important topic
Ability to modify the one level without affecting other level of scheme is called data independence
It is of 2 types

1- Physical data independence
Ability to modify the physical level schema without causing application program to be rewritten.
It improve performance

2• logical data independence

Ability to modify the conceptual level schema without causing application program to be rewritten.

it is harder to achieve as application programs are heavily dependent on it.

DATA LANGUAGES

DATA DEFINITION LANGUAGE -defines the  database schema ,the definition of database. Also known as DDL

DATA MANIPULATION LANGUAGE

also known as dml use to retrieve,delete,modify,insert

Types of DML
1- Procedural • what data is needed and how to get it

2 Non Procedural• what data is needed. Procedural generate more efficient codes.

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