> For the complete documentation index, see [llms.txt](https://salikadave26.gitbook.io/interview-questions/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://salikadave26.gitbook.io/interview-questions/web_development/databases.md).

# Databases

* Do you know database concepts and can you write a SQL query?
* Types of DBMS
* Would you prefer SQL or NoSQL for a given use case
* Explain commit and rollback in dbms
* SQL queries to explain GROUPBY, COUNT, MAX
* MongoDB v/s SQL, which one is better and why?
* Give query examples for joins in SQL.
* What are the steps used in PHP for the creation of the database records?
* Write a SQL query to print "1".
* How to change a stored SQL procedure?
* If somehow you delete a company's client database, what will be your next steps in handling this problem?
* Perform Natural Join on two tables.
* What do you understand by evolving & static databases?
* What is meant by Index-Free Adjacency and what kind of databases is it used?
* What is an entity in an RDBMS?
* What is Data Integrity?
* Design database to represent a tree structure. Also write queries to represent a parent-child pair.
* Write a SQL query to get Average Salary per department, with department name for the following schema: EMP(ID,NAME,SAL,D\_ID), DEPT(ID,NAME)
* Normalisation (apply on the given example)
* Indexes in DBMS, clustered index
* What is View?
* What is Trigger?
* What is difference between Process and Procedure?
* What is meant by Sharding? Why is it done?
* What is the difference between Vertical & Horizontal Sharding? State the databases that support each of them.
* Is there any difference between Sharding & Partitioning?