Rdbms Interview Questions and Answers

Last updated on Feb 06, 2023
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Rdbms Interview Questions

Relational database management system(RDBMS) is the DBMS which was designed for the relational databases. In other words, RDBMS is a subset of DBMS. In RDBMS, the relational database indicates that the data is stored in the structure format using the rows and the columns, i.e., tables and the values in each table are related to each other. RDBMS software executes the queries on the data like adding and updating the data. The application which comes under the RDBMS category is MySQL, Oracle, Informix, IBM DB2 and Microsoft SQL Server. RDBMS Interview Questions we are mentioning below will help you to gain enough knowledge about RDBMS.


  • RDBMS is in tabular form which is easy to understand
  • Provide Security
  • Easy to maintain, repair and test
  • Multiuser access to the database in real time
  • Easy to learn and implement.

All your questions related to RDBMS will be answered in the RDBMS interview questions for freshers mentioned below.

Most Frequently Asked Rdbms Interview Questions

Here in this article, we will be listing frequently asked Rdbms Interview Questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

Q1. How is RDBMS different from DBMS?
1. DBMS store data as a file RDBMS store data in tabular form.
2. DBMS handle a small amount of data RDBMS handle a large amount of data
3. Normalization is absent in DBMS Normalization is present in RDBMS
Q2. What is RDBMS and also explain its components?

RDBMS stands for the Relational Database Management System.RDBMS is the DBMS in which the data is stored in the tables, i.e., the values are stored in the rows and columns.

The components of RDBMS are:-
  • Tables:-Table holds the records for one entity whose information has to be saved. Here every row contains a record, and every column represents an attribute.
  • Forms:-Forms are used to enter the new record into the database.
  • Queries:-Queries are used to search the data across the tables to executes the queries.
  • Reports:-Reports are used to organize the query results in a proper way.
  • Macros:-provides the more features and the extra functionality to the database.
  • Modules:-Programmers can write the modules in their respective programming language and then run the blades when they are required from the database.
Q3. What is the difference between primary and foreign key?
S.no Primary Key Foreign Key
1. Value cannot be NULL Value can be NULL
2. Duplicate values not allowed Duplicate values are allowed
3. The primary key can only be one There can be multiple foreign key

Point to be noted:- Go through this Q&A very thoroughly as this is one of the critical RDBMS interview questions.

Q4. Explain the advantages of RDBMS?
  • It can be used by more than one users at the same time
  • Reduces the data redundancy and data duplication
  • RDBMS provided multiple interfaces
  • RDBMS is secure
Q5. Explain, why is RDBMS better than DBMS?
  • RDBMS handles a large quantity of Data.
  • RDBMS has very high-end security
  • RDBMS supports client-server architecture
  • RDBMS supports multiple users
  • RDBMS has minimum data redundancy
Q6. What do you mean by E-R Model & Object-oriented Model?

An Entity-Relationship model is primarily used to represent the real scenarios as entities. E-R model clearly defines the objects and the relations between the entities

An Object-oriented Model is mainly used to represent the real scenarios as objects. The objects with similar functions are grouped and linked to the other different purposes.in this model, the data can be reused in various missions.

Note:-This is the important RDBMS interview questions.

Q7. Explain all Codd's rules for relational database system?

Codd's rules or Codd's law are the set of 12 states which was developed by E.F. Codd in the year 1969-1970. Codd's law tells what is required from the database management system so that it can be considered relational.in other words, Codd's rules are rules for designing the RDBMS.

  • Rule 1: Information rule:-All the information has to be represented in only one way in the table
  • Rule 2:Guaranteed Access:-Every value in the table has to be accessible by the Table Name + Primary Key(Row) + Attribute(column).
  • Rule 3: Systematic treatment of NULL:-NULL values should be treated systematically
  • Rule 4: Active Online Catalog:-The catalog must be stored online
  • Rule 5: Powerful and Well-Structured Language: -A structured language should provide all access to the data which is stored in the database.
  • Rule 6: View Updation Rule:-All the view has to be updatable by the database system
  • Rule 7: Relational Level Operation:-There has to be the Insert, Delete, Update operations at every level of the relations
  • Rule 8: Physical Data Independence:-The changes in the Physical storage of the data should not affect the database system.
  • Rule 9: Logical Data Independence:-The changes in the logical structure of the database should not change the user view of the data.
  • Rule 10: Integrity Independence:-The Key and the Check constraints, the trigger, etc., should be stored in the Data Dictionary.
  • Rule 11: Distribution Independence: -A database should work correctly even if it is distributed across the network
  • Rule 12:Nonsubversion Rule:-If the low-level access has been allowed to a system; then it should not be able to subvert the integrity rules to alter the data.
Q8. What do you mean by super key, primary key, foreign key and candidate key?
  • Super Key:- This key recognizes the row in the table.
  • Primary Key:-This key is a column in the table which recognizes each row in the same table uniquely
  • Candidate Key:-This key does not have any repeated attribute
  • Foreign Key:-This key a column in the table to create a relationship with another table.

This particular RDBMS Question explains the importance of keys in the database.

Q9. Explain the difference between physical and logical data independence?

In Logical Data Independence the logical schema is modified without rewriting the application programs whereas in Physical Data Independence the physical schema is changed without rewriting the application programs.

Q10. What do you mean by cardinality and its types?

In the context of data models, cardinality means the relationship between two tables.

The connection can be of 4 types
  • One to One:-One row of the first table partners with one row of the second table
  • One to Many:-One row of the first table partners with more than one rows of the second table
  • Many to One:-More than one rows of the first table partners with one row of the second table
  • Many to Many:-More than one rows of the first table partners with more than one rows of the second table

In the context of Query Optimization, Cardinality refers to the uniqueness of the column in the table. A column having unique value will have high cardinality and vice-versa.

Development History

Relational database Management System was invented by invented by E. F. Codd in the year 1970 in IBM. The first RDBMS which became commercially available was the ORACLE in the year 1979.

Latest Databases

Some of the most popular RDBMS software are SQL Server, Oracle, PostgreSQL, SQLite, ThinkSQL, Cubrid.

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