1. What is DBMS?
It is a collection of programs that helps the user to create and maintain a database.
2. What is database system?
It is a combination of database and DBMS software.
3. Merits of DBMS:
Control redundancy.
Restrict unauthorized access
Allow multiple user interfaces
Enforce integrity constraints
Provide backup and recovery.
4.What are the levels of Levels of abstraction?
Physical level: The lowest level abstraction that describes how data is stored.
Logical level: Middle level of abstraction Which describes what data are stored and what is the relationship among the data
View level: Highest level of abstraction that describes only part of the database.
5. Two types of integrity rules
Entity Integrity: Primary key cannot be NULL
Referential Integrity: Foreign key can either be NULL or should be a primary key of another relation.
6. What is the difference between physical data independence and logical data independence?
Physical data independence: Modification in physical level should not affect logical level
Logical data independence: Modification in logical level should affect view level.
7. What is SDL?
SDL means Storage Definition Language
It specifies internal schema and also mapping between two schemas.
8. What is a DML compiler?
It helps to translate DML statements in the query language into low level instruction that is understood by the query evaluation engine.
9. What is relational algebra?
It is a procedural query language.
It is a set of operations that take one or two relations as input and produce a new relation.
10. What is transparent DBMS?
It is the DBMS that keeps its physical structure hidden from user.
11. If a relation is in 2NF, then
Every non-prime attribute is fully functionally dependent on each relation key.
12. The data type created by data abstraction process is called as
Class
13. An entity instance is a single occurence of
An entity type
14. A relation which is in BCNF is always in which NF
3NF
15. 2-phase locking protocol suffers from
Deadlocks
16. Time stamp protocol suffers from
Frequent aborts, cascading rollbacks
17. In generalization, the difference between members of an entity is
Maximized.
18. Some of the commonly used Aggregate functions are
SUM, AVG, COUNT
19. A locked file can be
* Modified by users with correct password
* Used to hide sensitive information.
20. A recursive foreign key
References its own relation.
Data Structures Question and answers:
http://netcompsci.blogspot.in/2013/06/data-structures-important-question-and.html
All the Best for UGC NET 2013!!!.
It is a collection of programs that helps the user to create and maintain a database.
2. What is database system?
It is a combination of database and DBMS software.
3. Merits of DBMS:
Control redundancy.
Restrict unauthorized access
Allow multiple user interfaces
Enforce integrity constraints
Provide backup and recovery.
4.What are the levels of Levels of abstraction?
Physical level: The lowest level abstraction that describes how data is stored.
Logical level: Middle level of abstraction Which describes what data are stored and what is the relationship among the data
View level: Highest level of abstraction that describes only part of the database.
5. Two types of integrity rules
Entity Integrity: Primary key cannot be NULL
Referential Integrity: Foreign key can either be NULL or should be a primary key of another relation.
6. What is the difference between physical data independence and logical data independence?
Physical data independence: Modification in physical level should not affect logical level
Logical data independence: Modification in logical level should affect view level.
7. What is SDL?
SDL means Storage Definition Language
It specifies internal schema and also mapping between two schemas.
8. What is a DML compiler?
It helps to translate DML statements in the query language into low level instruction that is understood by the query evaluation engine.
9. What is relational algebra?
It is a procedural query language.
It is a set of operations that take one or two relations as input and produce a new relation.
10. What is transparent DBMS?
It is the DBMS that keeps its physical structure hidden from user.
11. If a relation is in 2NF, then
Every non-prime attribute is fully functionally dependent on each relation key.
12. The data type created by data abstraction process is called as
Class
13. An entity instance is a single occurence of
An entity type
14. A relation which is in BCNF is always in which NF
3NF
15. 2-phase locking protocol suffers from
Deadlocks
16. Time stamp protocol suffers from
Frequent aborts, cascading rollbacks
17. In generalization, the difference between members of an entity is
Maximized.
18. Some of the commonly used Aggregate functions are
SUM, AVG, COUNT
19. A locked file can be
* Modified by users with correct password
* Used to hide sensitive information.
20. A recursive foreign key
References its own relation.
Data Structures Question and answers:
http://netcompsci.blogspot.in/2013/06/data-structures-important-question-and.html
All the Best for UGC NET 2013!!!.
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