A list of interview questions

Questions.md

1. Most common 4 HTTP VERB used in WEB API
   • GET,PUT,POST,DELETE
2. what is CORS ?
   • Cross-origin resource sharing (CORS) is a mechanism that allows restricted resources (e.g. fonts) on a web page to be requested from another domain outside the domain from which the resource originated.
   • Only web fonts and AJAX(XMLHttpRequest) requests faced CORS problem.
   • For simple CORS requests, the server only needs to add the following header to its response: Access-Control-Allow-Origin: *
3. what is CSRF attack?
   • Cross-site request forgery (XSRF or CSRF) is a method of attacking a Web site in which an intruder masquerades as a legitimate and trusted user. An XSRF attack can be used to modify firewall settings, post unauthorized data on a forum or conduct fraudulent financial transactions.
   • Prevention methods :- Synchronizer token pattern , Cookie-to-Header Token
4. what is XSS attack?
   • Cross-Site Scripting (XSS) attacks are a type of injection, in which malicious scripts are injected into otherwise benign and trusted web sites.
   • Prevention methods:- Sanitizing the input of form
5. Does python support switch/case statement in Python?
   • NO
6. Diff b/w mutable vs immutable datatypes?
   • The content of objects of immutable types cannot be changed after they are created.
   • mutable -> list, set, dict, byte array
   • immutable -> tuple, frozen set, int, float, str
7. What is the use of init.py file?
   • It is used to import a module in a directory, which is called package import.
8. Diff b/w range() and xrange()?
   • range() returns a list containing all the numbers from a to b
   • xrange() returns an iterator rather than a list, which makes it more lighter in terms of memory use
9. which method you have declare to make object iterable?
   • iter() with next()
10. Diff b/w docstrings vs comments?
    • A docstring is the documentation string for a function
11. Diff b/w classmethod vs staticmethod?
12. Ask about map(), filter(), reduce(), lambda function, list comprehension?
13. Usage of *args and **kwargs ?
    • Putting *args and/or **kwargs as the last items in our function definition's argument list allows that function to accept an arbitrary number of anonymous and/or keyword arguments.
14. Diff b/w RDMS and NoSQL?
15. what is normalization in DBMS?
    • Normalization is a process of organizing the data in database to avoid data redundancy, insertion anomaly, update anomaly & deletion anomaly. 1NF, 2NF, 3NF and BCNF(Boyce and Codd Normal Form )
16. List command of DDL, DML, and DCL?
    • Data Definition Language, which deals with database schemas and descriptions, of how the data should reside in the database. [ CREATE, ALTER, DROP, TRUNCATE, COMMENT, RENAME]
    • Data Manipulation Language, which deals with data manipulation and used to store, modify, retrieve, delete and update data in database. [ SELECT, INSERT, UPDATE, DELETE, MERGE, CALL]
    • Data Control Language which includes commands such as GRANT, and mostly concerned with rights, permissions and other controls of the database system. [GRANT, REVOKE]
17. Diff b/w DROP, DELETE and TRUNCATE command of SQL?
    • DROP command deleting the table and its structure from the data base.
    • DELETE command used for deleting the records from the table,and it removing the table space which is allocated by the data base, and returns number of rows deleted.
    • TRUNCATE command is also delete the records but it doesn't delete the table space which is created by the data base, and does not return number of deleted rows.