DBMS Interview Questions & Answers
Candidates, who have applied for the DBA jobs and going to attend the Database interview, can get the DBMS Interview Questions & Answers from this page and obtain the relevant jobs, they are applied for.
Freshers and Experienced aspirants, who want to prepared themselves for the interview, may get the related question and answers from this page of recruitmentresult.com as provided below:
1. What is Database?
Ans: A database is a logically coherent collection of data and gives a systematic and organized way of storing, managing and retrieving from collection of logically related information and can be used for representing some aspect of real world.
2. What is DBMS?
Ans: The acronym of DBMS is Database Management System and it is a collection of programs that enables user to create and maintain a database. It gives the facility of independent way of accessing data and should not be dependent on the application to access the information.
3. What is a Database system?
Ans: The database and DBMS software together is called as Database system and major difference between a file and database is that database has independent way of retrieving information while simple files do not.
4. What are the advantages of DBMS?
Ans: There are the various advantages of using the database by organization, some of its uses are as shown below:
- Unauthorized right of entry is constrained.
- Redundancy or data duplicacy is controlled.
- Enforcing integrity constraints.
- Providing backup and recovery facilities.
- Providing multiple user interfaces to accomplish the task.
5. What’s difference between DBMS and RDBMS?
Ans: Database Management Systems provides a systematic and organized way of storing, managing and retrieving from collection of logically related information and RDBMS also provides but above that it provides relationship integrity as shown below:
RDBMS (Relational Database Management Systems): DBMS + Referential Integrity.
6. What are the disadvantages in File Processing System?
Ans: There are some disadvantages of using the file processing system in database as furnished below:
- Data redundancy and discrepancy occurred.
- Difficult to accessing data information.
- Difficult to handle the data isolation.
- Data integrity in the files.
- Simultaneous access is not possible.
- Security (Protection) Problems.
7. What are E-R diagrams?
Ans: E-R diagram also known as Entity-Relationship diagram that shows the relationship between various tables in the database.
8. What are CODD rules?
Ans: There are 12 rules which a DBMS should adhere in order to get the logo of a true RDBMS which is created by the Dr. E. F. Codd In 1969.
- Information Rule
- Guaranteed access Rule.
- Systematic treatment of null values
- Dynamic on-line catalog based on the relational model
- Comprehensive data sub-language Rule
- View updating Rule
- High-level insert, update and delete
- Physical data independence.
- Logical data independence
- Integrity independence
- Distribution independence
- Non-subversion Rule
9. How many types of relationship exist in database designing?
Ans: There are three major types of the relationship models:
10. What is normalization?
Ans: In database, there is set of rules that have been recognized to help in the design of tables that are meant to be linked through relationships. This set of rules is known as Normalization. There are some benefits of Normalizing your database include as shown below:
- Helps in avoiding repetitive entries
- To reduce the required storage space
- Use to preventing the need to restructure existing tables to accommodate new data.
- Help to Increased speed and flexibility of queries, sorts, and summaries.
11. What is denormalization?
Ans: Denormalization is the procedure of setting one fact in various places (its vice-versa of Normalization). Only one valid reason exists for denormalizing a relational design – to improve performance. The sacrifice to presentation is that you boost redundancy in database.
12. What is extension and intension?
Ans: Extension: It is the number of tuples available in a table at any instance. This is time dependent.
Intension: It is a constant value that gives the name, structure of table and the constraints settled on it.
13. What is a view?
Ans: A view may be idea of as a virtual table, a table that does not really exist in its own right or database but as an alternative is derived from one or more underlying base table. We can say that, there is no stored file in database that direct represents the view in its place a definition of view is stored in data dictionary.
14. What is System R?
Ans: The System R was designed and developed at IBM San Jose Research Center over a period of 1974-79. It is a first of its kind and its function was to show that it is possible to build a Relational System that can be used in a real life environment to resolve real life problems, with performance at least comparable to that of existing system.
It has two subsystems are as indicated below:
- Research Storage
- System Relational Data System.
15. How is the data structure of System R different from the relational structure?
Ans: There are some major differences between Relational systems in System R as provided below:
- The Domains are not supported by the user.
- The Enforcement of candidate key uniqueness is not obligatory.
- Enforcement of entity integrity is non-compulsory
- Referential integrity is not imposed.
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