/    /  SQL- Interview questions Part 1

1. What is DBMS?

Answer: Database Management System (DBMS) is a software program which is used to create, maintain and control the database. The core functionality of the DBMS can be storage, retrieval and update of data.

Codd proposed some important functions and services that needs to be provided by the  DBMS software as below:

It should allow the storage of data, retrieval and update.

It should support the data dictionary which describes the metadata.

It should support for all types of transactions including concurrency.

It should have an option of recovering the database.

– It must support for access based authorization for database and access support from remote locations.

It should be enabled with constraints to ensure data in the database abides by certain rules.


2. What is RDBMS?

Answer: RDBMS can be abbreviated as Relational Database Management System. RDBMS can be termed as next level to DBMS model and this RDBMS represents the table model which can store the data into the collection of tables which are of rows and columns format. It also provides relations between the tables to retrieve the data from multiple tables.

The main difference between the DBMS and RDBMS (relational database management system) is that RDBMS databases store data in a tabular form, whereas DBMS database programs store data as files.

Examples are Oracle Database, MySQL Database, MSSQL Server etc.,


3. What is SQL?

Answer: SQL can be abbreviated as Structured Query Language (Earlier it was even used to refer as Sequel Query Language) and it is used mainly to communicate with the Databases. This is a standard language which is used to perform the Database creation, updating, insertion and deletion of data.



4. What do you mean by a Database?

Answer: Database can be understood as a collection of database objects which can be organized in the form for easy access, storing, retrieval and recovery of data. This is also generally called as structured form of data which can be accessed in many ways.

You can have the Databases for any domain or a business vertical to store the data can be like Banking Database, School Management Database etc.


5. What are Tables and Fields?

Answer: Table is a logical term which is used to store the data in Columns and Rows format. Columns can be considered as vertical, and whereas Rows are horizontal.  Columns in a table can be called as fields and the rows can be called as records.


Table: Employees table below consists the fields and records.

Fields: Emp ID, Emp Name, Date of Birth.

Data: 1234, Ravi, 1/05/1990.