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Database

1.

What is a database?

Ans:

A Database is a logical, consistent, and organized collection of data that can easily be accessed, managed, and updated. Databases, also known as electronic databases are structured to provide the facility of creation, insertion, updating of the data efficiently and are stored in the form of a file or set of files, on the magnetic disk, tapes, and other sort of secondary devices. Database mostly consists of the objects (tables), and tables include the records and fields. Fields are the basic units of data storage, which contain information about a particular aspect or attribute of the entity described by the database. DBMS is used for the extraction of data from the database in the form of queries.

2.

What is DBMS?

Ans:

DBMS stands for Database Management System. It is a collection of application programs that allow the user to organize, restore and retrieve information about data efficiently and as effectively as possible.

Some of the popular DBMSs are MySql, Oracle, Sybase, etc.

3.

What is RDBMS?

Ans:

Relational Database Management System(RDBMS) is based on a relational model of data that is stored in databases in separate tables and they are related to the use of a common column. Data can be accessed easily from the relational database using Structured Query Language (SQL).

4.

Enlist the advantages of DBMS.

Ans:

The advantages of DBMS includes:

  • Redundancy control
  • Restriction for unauthorized access
  • Provides multiple user interfaces
  • Provides backup and recovery
  • Enforces integrity constraints
  • Ensure data consistency
  • Easy accessibility
  • Easy data extraction and data processing due to the use of queries

5.

How is RDBMS different from DBMS?

Ans:

The key difference here, compared to DBMS, is that RDBMS stores data in the form of a collection of tables, and relations can be defined between the common fields of these tables. Most modern database management systems like MySQL, Microsoft SQL Server, Oracle, IBM DB2, and Amazon Redshift are based on RDBMS.

6.

What do you mean by transparent DBMS?

Ans:

The transparent DBMS is a type of DBMS that keeps its physical structure hidden from users. Physical structure or physical storage structure implies the memory manager of the DBMS, and it describes how the data stored on a disk.

7.

What do you mean by the durability in DBMS?

Ans:

Once the DBMS informs the user that a transaction has completed successfully, its effect should persist even if the system crashes before all its changes are reflected on the disk. This property is called durability. Durability ensures that once the transaction is committed into the database, it will be stored in the non-volatile memory and after that system failure cannot affect that data anymore.

8.

How do you communicate with an RDBMS?

Ans:

You have to use Structured Query Language (SQL) to communicate with the RDBMS. Using queries of SQL, we can give the input to the database, and then after processing of the queries database will provide us the required output.

9.

What are the integrity rules in DBMS?

Ans:

Data integrity is one significant aspect while maintaining the database. So, data integrity is enforced in the database system by imposing a series of rules. Those set of integrity is known as the integrity rules.

There are two integrity rules in DBMS:

Entity Integrity: It specifies that the "Primary key cannot have a NULL value."

Referential Integrity: It specifies that "Foreign Key can be either a NULL value or should be the Primary Key value of other relation."

10.

What is data abstraction in DBMS?

Ans:

Data abstraction in DBMS is a process of hiding irrelevant details from users. Because database systems are made of complex data structures so, it makes accessible the user interaction with the database.

Example: We know that most of the users prefer those systems which have a simple GUI that means no complex processing. So, to keep the user tuned and for making access to the data easy, it is necessary to do data abstraction. In addition, data abstraction divides the system into different layers to make the work specified and well defined.

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