11. What is the job of DBA?
Ans: A database administrator is a person or a group responsible for authorizing access to the database, for coordinating and monitoring its use, and for acquiring s/w and h/w resources as needed.
Ans: A database administrator is a person or a group responsible for authorizing access to the database, for coordinating and monitoring its use, and for acquiring s/w and h/w resources as needed.
12. Who are db designer?
Ans: Data base designers are responsible for identifying the data to be stored in the database and for
choosing appropriate structure to represent and store this data .
Ans: Data base designers are responsible for identifying the data to be stored in the database and for
choosing appropriate structure to represent and store this data .
13. What are different types of end
users?
Ans:
1. Casual end-users
2. Naive or parametric end users
3. Sophisticated end users
4. Stand alone users.
Ans:
1. Casual end-users
2. Naive or parametric end users
3. Sophisticated end users
4. Stand alone users.
14. What are the advantages of using
a dbms?
Ans:
1. Controlling redundancy.
2. Restricting unauthorized access.
3. Providing persistent storage for program objects and data structures.
4. Permitting inferencing and actions using rules.
5. Providing multi-user interfaces.
6. Representing complex relationships among data.
7. Enforcing integrity constraints.
8. Providing backups and recovery.
Ans:
1. Controlling redundancy.
2. Restricting unauthorized access.
3. Providing persistent storage for program objects and data structures.
4. Permitting inferencing and actions using rules.
5. Providing multi-user interfaces.
6. Representing complex relationships among data.
7. Enforcing integrity constraints.
8. Providing backups and recovery.
15. What are the disadvantages of
using a dbms?
Ans:
1. High initial investments in h/w, s/w, and training.
2. Generality that a DBMS provides for defining and processing data.
3. Overhead for providing security, concurrency control, recovery, and integrity functions.
Ans:
1. High initial investments in h/w, s/w, and training.
2. Generality that a DBMS provides for defining and processing data.
3. Overhead for providing security, concurrency control, recovery, and integrity functions.
16. What is a data model?
Ans: It is a collection of concepts that can be used to describe the structure of a database. It provides necessary means to achieve this abstraction. By structure of a database we mean the data types, relations, and constraints that should hold on the data.
Ans: It is a collection of concepts that can be used to describe the structure of a database. It provides necessary means to achieve this abstraction. By structure of a database we mean the data types, relations, and constraints that should hold on the data.
17. What are different categories of
data models?
Ans:
Ans:
1. High-level or conceptual data models.
2. Representational data models.
3. Low-level or physical data models.
- High level data models provide the concepts that are close to the way many users perceive data.
- Representational data models are provide concepts that provide the concepts that may be understood by end users but that are not too far removed from organization of data in the database.
- Physical data models describe the details of how data is stored in the computers.
18. What is schema?
Ans: The description of a data base is called the database schema , which is specified during database design and is not expected to change frequently . A displayed schema is called schema diagram .We call each object in the schema as schema construct.
Ans: The description of a data base is called the database schema , which is specified during database design and is not expected to change frequently . A displayed schema is called schema diagram .We call each object in the schema as schema construct.
19. What are types of schema?
Ans:
1. Internal schema.
2. Conceptual schema.
3. External schemas or user views.
Ans:
1. Internal schema.
2. Conceptual schema.
3. External schemas or user views.
20. What is Data independency?
Ans: Data independency is defined as the capacity to change the conceptual schema without having to change the schema at the next higher level. We can define two types of data independence:
1. Logical data independence.
2. Physical data independence.
LDI is the capacity to change the conceptual schema without having to change external schemas or application programs.
PDI is the capacity to change the internal schema without having to change conceptual (or external) schemas.
Ans: Data independency is defined as the capacity to change the conceptual schema without having to change the schema at the next higher level. We can define two types of data independence:
1. Logical data independence.
2. Physical data independence.
LDI is the capacity to change the conceptual schema without having to change external schemas or application programs.
PDI is the capacity to change the internal schema without having to change conceptual (or external) schemas.
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