SQL Server Interview Questions and Answers

Part 1 - Stack, Heap, Boxing, Unboxing, Array, ArrayList, Generics, Threading
Question 1 :- Explain difference between .NET and C# ?
Question 2 :- .NET Framework vs .NET Core vs .NET 5.0
Question 3 :- What is IL ( Intermediate Language) Code ?
Question 4 :- What is the use of JIT ( Just in time compiler) ?
Question 5 :- Is it possible to view IL code ?
Question 6 :- What is the benefit of compiling in to IL code ?
Question 7 :- Does .NET support multiple programming languages ?
Question 8 :- What is CLR ( Common Language Runtime) ?
Question 9 :- What is managed and unmanaged code ?
Question 10 :- Explain the importance of Garbage collector ?
Question 11 :- Can garbage collector claim unmanaged objects ?
Question 12 :- What is the importance of CTS ?
Question 13 :- Explain CLS ?
Question 14 :- Difference between Stack vs Heap ?
Question 15 :- What are Value types & Reference types?
Question 16 :- Explain boxing and unboxing ?
Question 17 :- What is consequence of boxing and unboxing ?
Question 18 :- Explain casting, implicit casting and explicit casting ?
Question 19 :- What can happen during explicit casting ?
Question 20 :- Differentiate between Array and ArrayList ?
Question 21 :- Whose performance is better array or arraylist ?
Question 22 :- What are generic collections ?
Question 23 :- What are threads (Multithreading)?
Question 24 :- How are threads different from TPL ?
Question 25 :- How do we handle exceptions in C#(try/catch)?
Question 26 :- What is the need of finally?
Question 27 :- Why do we need the out keyword ?
Question 28 :- What is the need of Delegates ?
Question 29 :- What are events ?
Question 30 :- What's the difference between Abstract class and interface ?

Part 2 - Questions on Delegates, Event and Delegates vs Events.
Question 31  :- What is a delegate and How to create a delegate ?
Question 32  :- Where have you used delegates ?
Question 33  :- What is a Multicast delegates ?
Question 34  :- What is a Event ?
Question 35  :- How to create a event ?
Question 36  :- Delegate vs Events.

Part 3 - OOP, Abstraction, Encapsulation, Inheritance, Overriding & overloading.
Question 37 :- Why do we need OOP ?
Question 38 :- What are the important pillars of OOPs ?
Question 39 :- What is a class and object ?
Question 40 :- Abstraction vs Encapsulation?
Question 41 :- Explain Inheritance ?
Question 42 :- Explain virtual keyword ?
Question 43 :- What is overriding ?
Question 44 :- Explain overloading ?
Question 45 :- Overloading vs Overriding ?

Part 4 - Polymorphism, Static vs Dynamic polymorphism and operator overloading.
Question 46 :- What is polymorphism ?
Question 47 :- Can polymorphism work with out inheritance ?
Question 48 :- Explain static vs dynamic polymorphism ?
Question 49 :- Explain operator overloading ?

Part 5 - Tricky Questions around Abstract classes and Interfaces.
Question 50  :- Why do we need Abstract classes ?
Question 51  :- Are Abstract methods virtual ?
Question 52  :- Can we create a instance of Abstract classes ?
Question 53  :- Is it compulsory to implement Abstract methods ?
Question 54  :- Why simple base class replace Abstract class ?
Question 55  :- Explain interfaces and why do we need it ?
Question 56  :- Can we write logic in interface ?
Question 57  :- Can we define methods as private in interface ?
Question 58  :- If i want to change interface what's the best practice ?
Question 59  :- Explain Multiple inheritance in Interface ?
Question 60  :- Explain Interface Segregation principle ?
Question 61  :- Can we create instance of interface ?
Question 62  :- Can we do Multiple inheritance with Abstract classes ?

Part 6 - Answering the most asked Question "Abstract classes vs Interface".
Question 63 :- Difference between Abstract Class & Interfaces?

Part 7 - Questions around constructors & parent child constructor.
Question 64  :- Why do we need constructors ?
Question 65  :- In parent child which constructor fires first ?
Question 66  :- How are initializers executed ?
Question 67  :- How are static constructors executed in Parent child ?
Question 68  :- When does static constructor fires ?

Part 8 - Questions around Shadowing, Sealed, Nested classes and partial classes.
Question 69 :- What is Shadowing?
Question 70 :- Explain method hiding?
Question 71 :- Shadowing vs Overriding ?
Question 72 :- When do we need Shadowing ?
Question 73 :- Explain Sealed Classes ?
Question 74 :- Can we create instance of sealed classes ?
Question 75 :- What are nested classes and when to use them ?
Question 76 :- Can Nested class access outer class variables ?
Question 77 :- Can we have public, protected access modifiers in nested class ?
Question 78 :- Explain Partial classes ?
Question 79 :- In What scenarios do we use partial classes ?

Part 9 - Questions Around SOLID principles , Dependency injection (DI) and IOC
Question 80 :- What is SOLID ?
Question 81 :- What is the full form of SOLID ?
Question 82 :- What is the goal of SOLID ?
Question 83 :- Explain SRP with A example ?
Question 84 :- What is the benefit of SRP ?
Question 85 :- Explain OCP with a example ?
Question 86 :- What is the  benefit of OCP ?
Question 87 :- Can you explain LISKOV Principle and it's violation?
Question 88 :- How can we fix LISKOV Problem ?
Question 89 :- Explain Interface Segregation Principle ?
Question 90:- Is there a connection between LISKOV and ISP ?
Question 91 :- Define dependency inversion ?
Question 92 :- What is higher level module and lower level module ?
Question 93 :- How does dependency inversion benefit, show with an example ?
Question 94 :- Will only Dependency inversion solve decoupling problem ?
Question 95 :- Why do developers  move object creation outside high lever module ?
Question 96 :- Explain IOC ( Inversion of Control) ?
Question 97 :- Explain Dependency Injection with an example ?
Question 98 :- Is SOLID, IOC and DI design pattern or Principle?
Question 99 :- Is only SOLID Enough for good code/ architecture ?

Part 10- Explain & Differentiate Composition, Aggregation and Association in C#.
Question 100 :- What are the different types of "USING/HAS A" relationship ?
Question 101 :- What is a composition relationship ?
Question 102 :- Explain Aggregation ?
Question 103 :- Explain Association ?
Question 104 :- Differentiate between Composition vs Aggregation vs Association ?
Question 105 :- UML Symbols for Composition, Aggregation and Association

Part 11 - Crack questions on Stack, Heap, Boxing, Unboxing, Value &  reference types
Question 106 :- Explain stack and Heap ?
Question 107 :- Where are stack and heap stored ?
Question 108 :- What goes on stack and what goes on heap ?
Question 109:- How is the stack memory address arranged ?
Question 110 :- How is stack memory deallocated LIFO or FIFO ?
Question 111 :- How are primitive and objects stored in memory?
Question 112 :- Can primitive data types be stored in heap ?
Question 113 :- Explain value types and reference types ?
Question 114 :- Explain byval and byref ?
Question 115 :- Differentiate between copy byvalue and copy byref ?
Question 116 :- What is boxing and unboxing ?
Question 117 :- Is boxing unboxing good or bad ?
Question 118 :- Can we avoid boxing and unboxing ?
Question 119 :- What effect does boxing and unboxing have on performance ?
Question 120 :- Are string allocated on stack or heap ?
Question 121 :- How many stack and heaps are created for an application ?
Question 122 :- How are stack and heap memory deallocated ?
Question 123 :- Who clears the heap memory ?
Question 124 :- Where is structure allocated Stack or Heap ?
Question 125 :- Are structures copy byval or copy byref ?
Question 126 :- Can structures get created on Heap ?

Part 12 - What is Garbage collector, Managed vs UnManaged code, Dispose Pattern, Memory Leaks, weak VS strong references ?

Question 127: - Explain Garbage collector (GC)?
Question 128:- How does Garbage collector know when to clean the objects ?
Question 129 :- Is there a way we can see this Heap memory ?
Question 130 :- Does Garbage collector clean primitive types ?
Question 131: - Managed vs UnManaged code/objects/resources?
Question 132:- Can garbage collector clean unmanaged code ?
Question 133:- Explain Generations  ?
Question 134:- What is GC0,GC1, and  GC2 ?
Question 135:- Why do we need Generations ?
Question 136:- Which is the best place to clean unmanaged objects ?
Question 137:- How does GC behave when we have a destructor ?
Question 138:- What do you think about empty destructor ?
Question 139:- Explain the Dispose Pattern?
Question 140 :- Finalize vs Destructor ?
Question 141:- What is the use of using keyword ?
Question 142:- Can you force Garbage collector ?
Question 143:- Is it a good practice to force GC ?
Question 144:- How can we detect a memory issues ?
Question 145:- How can we know the exact source of memory issues ?
Question 146 :- What is a memory leak ?
Question 147 :- Can .NET Application have memory leak as we have GC?
Question 148:- How to detect memory leaks in .NET applications ?
Question 149:- Explain weak and strong references ?
Question 150 :- When will you use weak references ?

Lesson 13 :- Questions around Design Pattern Basics, Types, Singleton Pattern, Prototype, Template and Adapter.

Question 151:- What are design patterns?
Question 152 :- Which are the different types of design patterns?
Question 153 :- Explain structural , Behavioral and Creational design pattern ?
Question 154:- Explain Singleton Pattern and the use of the same?
Question 155:- How did you implement singleton pattern?
Question 156:- Can we use Static class rather than using a private constructor?
Question 157:- Static vs Singleton pattern?
Question 158:- How did you implement thread safety in Singleton?
Question 159:- What is double null check in Singleton?
Question 160:- Can Singleton pattern code be made easy with Lazy keyword?
Question 161:- Can we rid of this double null check code?

Lesson 14 :- Repository Pattern and Unit of Work Design Pattern Interview Questions.

Question 162:- What is the use of repository pattern?
Question 163:- Is Dal (Data access Layer) and Repository same? 
Question 164:- What is Generic repository pattern ?
Question 165:- Is abstraction the only benefit of Repository?
Question 166:- How to implement transaction in repository?
Question 167:- What is Unit of work design pattern?
Question 168:- Do we need repository pattern as EF does almost the same work?
Question 169:- Did you do unit testing with Repository ?
Question 170:- How does repository pattern make unit testing easy?
Question 171:- How can we do mock testing with Repository?

Lesson 15:- Most asked Factory Pattern, DI and IOC Interview Questions.

Question 172 :- What is Factory pattern and how does it benefit?
Question 173 :- How does centralizing object creation helps in loose coupling ?
Question 174 :- What is IOC and DI ?
Question 175 :- DI vs IOC ?
Question 176 :- What is a service locator ?
Question 177:- Service Locator vs DI ?
Question 178 :- Which is good to use Service Locator or DI ?
Question 179 :- Can not we use a simple class rather than interface for DI ?
Question 180 :- Is DI a Factory Pattern?
Question 181 :- So If you just centralize object creation is it Factory pattern?
Question 182 :- Static DI and Dynamic DI ?
Question 183 :- In which scenarios to use Static DI vs Dynamic DI ?

Lesson 16 :- The Real Factory and Abstract Factory Patterns.

Question 184 :- The real Factory pattern ?
Question 185 :- Factory Method vs Factory pattern ?
Question 186 :- How are new behaviors created in FP ?
Question 187 :- What is Abstract Factory Pattern ?
Question 188 :- Does Abstract Factory Pattern use FP inside ?
Question 189 :- Explain Simple Factory Pattern ?
Question 190 :- Simple Factory vs Factory (Factory Method) vs Abstract Factory ?
Question 191 :- How to remove IF conditions from Simple Factory?

Basic 25 Questions - Part 1.

Basic Planning of ASP.NET Interview scope

Question 1 :- What is ASP .NET MVC Core ?
Question 2 :- Differentiate between ASP .NET Webforms vs MVC vs MVC core ?
Question 3 :- Explain MVC Architecture ?
Question 4 :- Why do we have wwwroot folder ?
Question 5 :- Explain the importance of appsettings.json ?
Question 6 :- How to read configurations from appsettings.json ?
Question 7 :- What is dependency injection ?
Question 8 :- Why do we need dependency injection ?
Question 9 :- How do we implement dependency injection ?
Question 10 :- What is the use of Middleware ?
Question 11 :- How to create a Middle ware ?
Question 12 :- What does startup.cs file do ?
Question 13 :- ConfigureServices vs Configure method ?
Question 14 :- Explain the different Ways of doing DI?
Question 15 :- Explain Scoped vs Transient vs Singleton ?
Question 16 :- What is Razor ?
Question 17 :- How to pass Model data to a View ?
Question 18 :- What is the use of Strongly typed views ?
Question 19 :- Explain the concept of ViewModel in MVC ?
Question 20 :- What is Kestrel Web Server ?
Question 21 :- Why Kestrel when we have IIS server ?
Question 22 :- What is the concept of Reverse proxy ?
Question 23 :- What are cookies ?
Question 24 :- What is the need session management ?
Question 25 :- What are the various ways of doing Session management in ASP.NET ?

Session management session and cookies - Part 2.
Question 26  :- What exactly is a session ?
Question 27  :- Explain "HTTP is a stateless protocol" ?
Question 28  :- What are various way of doing session management ?
Question 29  :- Are sessions enabled by default ?
Question 30  :- How to enable sessions in MVC core ?
Question 31  :- Are sessions variables shared(global) between users ?
Question 32  :- Do session variables use cookies ?
Question 33  :- What is a cookie ?
Question 34  :- Explain idle time out in sessions ?
Question 35  :- What does a Context means in HTTP ?

Session management viewdata,viewbag and viewmodel - Part 3.
Question 36 :- When should we use viewdata ?
Question 37 :- How to pass data from controller to view ?
Question 38 :- In same request can viewdata persist across actions ?
Question 39 :- ViewData vs ViewBag
Question 40 :- How does ViewBag work internally?
Question 41 :- Explain ViewModel?
Question 42 :-  ViewBag vs ViewModel whats the best practice?

Session management Tempdata - Part 4.
Question 43  :- Explain tempdata ?
Question 44  :- Can tempdata persist across action redirects ?
Question 45  :- How is tempdata different from viewdata ?
Question 46  :- If tempdata is read is it available for next request ?
Question 47  :- How to persist tempdata ?
Question 48  :- What does Keep do in tempdata ?
Question 49  :- Explain Peek in tempdata ?
Question 50  :- How is tempdata different from session variables ?
Question 51  :- If i restart the server does tempdata,session stay ?
Question 52  :- Is tempdata private to a user ?
Question 53  :- ViewData vs ViewBag vs Tempdata vs Session variables?

WebAPI and REST - Part 5.
Question 54  :- What is  WebAPI ?
Question 55  :- What is the advantage of WebAPI ?
Question 56  :- Explain REST and Architectural constraints of REST?
Question 57  :- Can we use  TCPIP protocol with Web API?
Question 58  :- How WebAPI different from MVC controller ?
Question 59  :- What is content negotiations in Web API ?
Question 60  :- WebAPI vs WCF ?
Question 61  :- WCF REST vs WebAPI REST ?
Question 62  :- How to return HTTP status codes ?
Question 63  :- For error which status code is returned ?
Question 64  :- How did you secure your web API ?
Question 65  :- How do current JS frameworks work with webAPI ?

JWT Token, Principal, Claim, Roles, Refresh Token, OpenId, OAuth - Part 6.
Question 66 :- How does  Token based Authentication works?
Question 67 :- Why is it called JWT Token?
Question 68 :- Explain the 3 sections of JWT Token?
Question 69 :- What are Identity and claims ?
Question 70 :- Differentiate between Authentication VS Authorization ?
Question 71 :  Claims vs Roles ?
Question 72 :- Principal vs Identity
Question 73 :- Can we put critical information in JWT Token ?
Question 74 :- How do you create JWT Token in MVC ?
Question 75 :- What HTTP status code do you send for unauthorized access ?
Question 76 :- Where is Token Checked in ASP.NET MVC ?
Question 77 :- What is use of Authorize Attribute ?
Question 78 :- How did you implement JWT token security ?
Question 79 :- How do we send tokens  from Client Side ?
Question 80 :- From Javascript, Jquery, Angular etc , How is token passed ?
Question 81 :- Increase UX experience in Mobile apps to avoid relogin ?
Question 82 :- What are refresh tokens ?
Question 83 :- How does Refresh token work ?
Question 84 :- Access tokens vs Refresh Tokens ?
Question 85 :- Whose expiry time is more Access tokens or Refresh tokens?
Question 86 :- Explain revocation of Refresh token  ?
Question 87 :- How to extract Principal from a Token ?
Question 88 :- What is the best practice to store tokens at client side?
Question 89 :- If we store JWT in cookie how to save from XX attacks?
Question 90 :- What OAUTH  and OpenID ?
Question 91 :- When should we use what?
Question 92 :- What is Identity Server?
Question 93 :- How to achieve single sign on ?
Question 94 :- What are scopes in Identity Server ?

25 Interview Questions on Angular basic concepts - Part 1.
Question 1 :- Whats the use  of Angular ?
Question 2 :- What are directives in Angular  ?
Question 3 :- Explain the different types of Angular directives  ?
Question 4 :- Explain the importance of NPM and Node_Modules folder ?
Question 5 :- Explain the importance of Package.json file in Angular ?
Question 6 :- What is typescript and why do we need it ?
Question 7 :- Explain importance of Angular CLI ?
Question 8 :- Explain the importance of Component and Modules ?
Question 9 :- What is a decorator in Angular ?
Question 10 :- What are Annotation or MetaData ?
Question 11 :- What is a template ?
Question 12 :- Explain the four types of Data bindings in Angular ?
Question 13 :- Explain architecture of Angular ?
Question 14 :- What is SPA in Angular ?
Question 15 :- How to implement SPA in Angular ?
Question 16 :- How to implement routing in Angular ?
Question 17 :- Explain Lazy Loading ?
Question 18 :- How to implement Lazy Loading in Angular ?
Question 19 :- Define Services ?
Question 20 :- What is Dependency Injection ?
Question 21 :- How to implement Dependency Injection ?
Question 23 :- Whats the benefit of Dependency Injection ?
Question 24 :- Differentiate between ng serve and ng build ?
Question 25 :- Explain the --prod parameter in ng build ?

Covered 6 Important questions on ViewChild and ViewChildren in Angular - Part 2.
Question 26 :- Explain ViewChild and ViewChildren ?
Question 27 :- Why do we need Template reference variables ?
Question 28 :- What is ContentProjection ?
Question 29 :- Explain Content projection Slot ?
Question 30 :- What is ContentChild and ContentChildren?
Question 31 :- ViewChild vs ViewChildren vs ContentChild vs ContentChildren ?

Questions around Angular component lifecycle - Part 3.
Question 32 :- Explain the importance of Component life cycle ?
Question 33 :- Explain events and sequence of component life cycle ?
Question 34 :- constructor vs ngOnInit() ?

Tricky Interview questions on HTTP calls, Emitters & Routing - Part 4.
Question 35 :- How to make HTTP calls using Angular ?
Question 36 :- What is the need of Subscribe function ?
Question 37 :- How to handle errors when HTTP fails ?
Question 38 :- How to pass data between components ?
Question 39 :- What are input , output and event emitters ?
Question 40 :- How to pass data during routing ?
Question 41 :- Is it a good practice to pass data using services ?

Questions on Angular Pipes - Part 5.
Question 42 :- What is the need of Angular Pipes ?
Question 43 :- Can you name some built-in Angular pipes ?
Question 44 :- How to create Custom pipes in Angular ?

Ten important questions on RxJS (Reactive Extensions for JavaScript) - Part 6
Question 45 :- What is the fullform of RxJS ?
Question 46 :- What is the purpose of RxJS ?
Question 47 :- What are Observables and Observers ?
Question 48 :- Explain the use of Subscribe with sample code ?|
Question 49 :- How to unsubscriber in RxJS ?
Question 50 :- Explain the concept of operators with sample code?
Question 51 :- How to install RxJS ?
Question 52 :- Differntiate between promise and RxJS ?
Question 53 :- In Angular where have you used RxJS?
Question 54 :- Which operators have used from RxJS ?
Question 55 :- What is the Push/Reactive vs Pull/Imperative?

Essential questions around Interceptors - Part 7.
Question 56 :- What are Interceptors in Angular?
Question 57 :- How to implement Interceptors?
Question 58 :- Give some use of Interceptors?
Question 59 :- Can we provide multi-Interceptors?

13 Important Interview Questions on Angular Validations - Part 8
Question 60 :- What are two ways of doing validation in Angular?
Question 61 :- Template driven forms VS Reactive Forms?
Question 62 :- In what situations you will use what?
Question 63 :- Explain template reference variables ?
Question 64 :- How do we implement Template driven forms?
Question 65 :- How do we implement Reactive forms ?
Question 66 :- How can we implement composite validations?
Question 67 :- How to create dynamic validation ?
Question 68 :- How to check if overall validation and specific validations are good ?
Question 69 :- Can you talk about some inbuilt validators ?
Question 70:- How can you create your own custom validator ?
Question 71:- Can we implement angular validators with out FORM tag ?
Question 72:- What is [ngModelOptions]="{standalone: true}" ?

Basic Architecture Interview Questions
1. Explain your project architecture?
2. Architecture style VS Architecture pattern VS Design pattern.
3. What are design patterns?
4. Which are the different types of design patterns?
5. Which design pattern have you used in your project?
6. Explain Singleton Pattern and the use of the same?
7. How did you implement singleton pattern?
8. Can we use Static class rather than using a private constructor?
9. Static vs Singleton pattern?
10. How did you implement thread safety in Singleton?
11. What is double null check in Singleton?
12. Can Singleton pattern code be made easy with Lazy keyword?
13. Can we rid of this double null check code?
14. What are GUI architecture patterns, can you name some?
15. Explain term Separation of concerns ( SOC ) ?
16. Explain MVC Architecture Pattern?
17. Explain MVP Architecture pattern?
18. What is the importance of interface in MVP ?
19. What is passive view?
20. Explain MVVM architecture pattern?
21. What is the difference between MVP and MVVM
22. What is a ViewModel?
23. When to use what MVP / MVC / MVVM?
24. MVC vs MVP vs MVVM?
25. Layered architecture vs Tiered?

Architecture Design Patterns Questions & Answers - Part 2

Solid Principles
26. What is SOLID?
27. What is the full form of SOLID?
28. What is the goal of SOLID ?
29. Explain SRP with a example ?
30. What is the benefit of SRP ?
31. Explain OCP with a example ?
32. What is the benefit of OCP ?
33. Can you explain LISKOV Principle and its violation ?
34. How can we fix LISKOV Problem ?
35. Explain Interface Seggregation Principle?
36. Is there a connection between LISKOV and ISP ?
37. Define depedency inversion?
38. What is higher level module and lower level module ?
39. How does depedency inversion benefit , show with an example ?
40. Will only Dependency inversion solve decoupling problem ?
41. Why do developers move object creation outside high level module?
42. Explain IOC (Inversion of control) ?
43. Explain Dependency Injection with an example?
44. Is SOLID, IOC and DI design pattern or principle?
45. Is only SOLID Enough for good code/architecture ?

Architecture Design Patterns Questions & Answers - Part 3

Repository Pattern and UOW
46. What is the use of repository pattern?
47. Is Dal (Data access Layer) and Repository same?
48. What is Generic repository pattern ?
49. Is abstraction the only benefit of Repository?
50. How to implement transaction in repository?
51. What is Unit of work design pattern
52. Do we need repository pattern as EF does almost the same work?
53. Did you do unit testing with Repository ?
54. How does repository pattern make unit testing easy?
55. How can we do mock testing with Repository?

Architecture Design Patterns Questions & Answers - Part 4

Factory Pattern , Abstract Factory , DI , IOC , Service locator
56. What is Factory pattern and how does it benefit?
57. How does centralizing object creation helps in loose coupling ?
58. Question 174 :- What is IOC and DI ?
59. DI vs IOC ?
60. What is a service locator ?
61. What is a service locator ?
62. Which is good to use Service Locator or DI ?
63. Can not we use a simple class rather than interface for DI ?
64. Is DI a Factory Pattern?
65. So If you just centralize object creation is it Factory pattern?
66. Static DI and Dynamic DI ?
67. In which scenarios to use Static DI vs Dynamic DI ?

Architecture Design Patterns Questions & Answers - Part 5

Factory and Abstract Factory pattern continued.
68. The real Factory pattern ?
69. Factory Method VS Factory pattern ?
70. How are new behaviors created in Factory pattern ?
71. What is Abstract Factory Pattern ?
72. Does Abstract Factory Pattern use FP inside ?
73. Explain Simple Factory Pattern ?
74. Simple Factory vs Factory (Factory Method) vs Abstract Factory ?
75. How to remove IF conditions from Simple Factory?

Architecture Interview Questions and Answer eBook - Part 6

Must and Basic Questions on
SQL Server - Part 1

Question 1  :- Explain
normalization ?
Question 2  :- How to
implement normalization ?
Question 3  :- What is
denormalization ?
Question 4  :- Explain OLTP
vs OLAP ?
Question 5  :- Explain
1st,2nd and 3rd Normal form ?
Question 6  :- Primary Key
vs Unique key ?
Question 7  :- Differentiate
between Char vs Varchar ?
Question 8  :- Differentiate
between Char vs NChar ?
Question 9  :- Whats the
size of Char vs NChar ?
Question 10 :- What is the use of
Index ?
Question 11 :- How does it make
search faster?
Question 12 :- What are the two
types of Indexes ?
Question 13 :- Clustered vs
Non-Clustered index
Question 14 :- Function vs Stored
Procedures
Question 15 :- What are triggers
and why do you need it ?
Question 16 :- What are types of
triggers ?
Question 17 :- Differentiate
between After trigger vs Instead Of ?
Question 18 :- What is need of
Identity ?
Question 19 :- Explain
transactions and how to implement it ?
Question 20 :- What are inner
joins ?
Question 21 :- Explain Left join
?
Question 22 :- Explain Right join
?
Question 23 :- Explain Full outer
joins ?
Question 24 :- Explain Cross
joins ?

Interview Questions around
essential concepts of SQL Server - Part 2
Question 25:-Why do we need UNION
?
Question 26:-Differentiate
between Union vs Union All ?
Question 27:-can we have unequal
columns in Union?
Question 28:-Can column have
different data types in Union ?
Question 29:- Which Aggregate
function have you used ?
Question 30:- When to use Group
by ?
Question 31:- Can we select
column which is not part of group by ?
Question 32:- What is having
clause ?
Question 33:- Having clause vs
Where clause
Question 34:- How can we sort
records ?
Question 35:- Whats the default
sort ?
Question 36:- How can we remove
duplicates ?
Question 37:- Select the first
top X records ?
Question 38:- How to handle NULLS
?
Question 39:- What is use of wild
cards ?
Question 40:- What is the use of
Alias ?
Question 41:- How to write a case
statement ?
Question 42:- What is self
reference tables ?
Question 43:- What is self join ?
Question 44:- Explain the between
clause ?

Important questions on
SubQuery and Cor-related Queries in SQL-Part 3
Question 45:- Explain SubQuery?
Question 46:- Can inner Subquery
return multiple results?
Question 47:- What is Co-related
Query?
Question 48:- Differentiate
between Joins and SubQuery?
Question 49:- Performance Joins
vs SubQuery?

How to Find Nth Highest Salary
? - Part 4
Question 50:- Find NTH Highest
Salary in SQL.

Covered Questions on finding
Nth highest using co-related & TSQL-Part 5
Question 51:-  Select the
top nth highest salary using correlated Queries?
Question 52:-  Select top
nth using using TSQL
Question 53:-  Performance
comparison of all the methods.

Questions around SQL Server
CTE(Common Table Expressions) - Part6
Question 54 :- What is CTE ?
Question 55 :- Can we execute CTE
multiple times ?
Question 56 :- What is use of CTE
?
Question 57 :- How to write a
recursive CTE ?
Question 58 :- Can we see some
real world examples of CTE ?
Question 59 :- Can we perform
insert updates on CTE?
Question 60 :- Does is update the
tables physically ?
Question 61 :- What are temporary
tables?
Question 62 :- Temp tables vs CTE
Question 63 :- Performance CTE vs
Temp

Questions around Window
functions, Rank, Dense_Rank and RowNumber - Part 7
Question 64 :- What are window
functions in SQL ?
Question 65 :- What does
partition clause in window function ?
Question 66 :- So is window
function partition similar to group by ?
Question 67 :- What is difference
between Rank vs Dense_Rank ?

Questions around Delete
Duplicate Records scenarios - Part 8
Question 68 :- Find records which
are unique.
Question 69 :- Delete Duplicate
Records (with Id).
Question 70 :- Delete Duplicate
Records (without Id).
Question 71 :- Delete Duplicate
Records (using CTE).
Question 72 :- Delete Millions of
Duplicate Records without performance impact.

JavaScript basics Interview questions with answers.
Question 1 :- Why do we call JavaScript as dynamic language
Question 2 :- how does JavaScript determine data types ?
Question 3 :- What is typeof ?
Question 4 :- How to check data type in JavaScript ?
Question 5 :- What are different datatypes in JavaScript ?
Question 6 :- Explain Undefined Data types ?
Question 7 :- What is Null ?
Question 8 :- Differentiate between Null and Undefined ?
Question 9 :- Explain Hoisting ?
Question 10 :- Are JavaScript initialization hoisted ?
Question 11 :- What are global variables ?
Question 12 :- What are the issues with Global variables ?
Question 13 :- What happens when you declare variable with out VAR ?
Question 14 :- What is Use Strict ?
Question 15 :- How to force developers to use Var keyword ?
Question 16 :- How can we handle Global Variables ?
Question 17 :- How can we avoid Global variables ?
Question 18 :- What are Closures ?
Question 19 :- Why do we need Closures ?
Question 20 :- Explain IIFE ?
Question 21 :- What is the use of IIFE ?
Question 22 :- What is name collision in global scope ?
Question 23 :- IIFE vs Normal Function
Question 24 :- What are design patterns ?
Question 25 :- Which is the most used design pattern
Question 26 :- What is module Pattern and revealing module pattern ?
Question 27 :- How man ways are there to create JavaScript objects ?
Question 28 :- How can we do inheritance in JavaScript ?
Question 29 :- What is prototype in JavaScript ?
Question 30 :-Explain Prototype chaining ?
Question 31 :- What is Let Keyword ?
Question 32 :- Are Let variables hoisted ?
Question 33 :- Explain Temporal Dead Zone ?
Question 34 :- Let vs Var
Question 35 :- String Concatenation and Arithmetic puzzle

7 Important JavaScript Interview Questions on ES6 & JavaScript Functions.
Question 36 :- What is class in ES6 ?
Question 37 :- So with class Keyword does it imply JavaScript is a OOP language ?
Question 38 :- Differentiate between class and normal function ?
Question 39 :- What is a Arrow function ?
Question 40 :- Why do we use Arrow function ?
Question 41 :- Differentiate between Arrow vs Normal Function ?
Question 42 :- Does Arrow function create its own this ?

Technical Questions on Sync, Async, Threading, Event Loop, Blocking and Non-Blocking and Callback Queue.
Question 43. Explain Synchronous execution ?
Question 44. What is a call Stack ?
Question 45. What is a blocking call ?Question 46. How to avoid blocking calls ?
Question 47. Explain Asynchronous execution ?
Question 48. Synch vs Asynch ?
Question 49. How can we do Asynch calls ?
Question 50. What is a thread ?
Question 51. Explain Multi-threading ?
Question 52. Is JavaScript Multi-threaded ?
Question 53. Then how does Settimeout run ?
Question 54. What is a WebAPI/Browser API ?
Question 55. What is a Event loop and callback queue?
Question 56. Eventloop and Callback code question

JavaScript Promises, Chaining, callbacks, Asynch, Await, Micro,Macro, Webworker.
Question 57. What are promises in JavaScript?
Question 58. How to catch error in promises ?
Question 59. What are callbacks ?
Question 60. Explain Promise chaining ?
Question 61. Three States of Promises ?
Question 62. Explain Async and Await ?
Question 63. Why to make a promise synch?
Question 64. Does Async represent a promise ?
Question 65. Can we use Async with out Await ?
Question 66. What are Micro and Macro queues ?
Question 67. Who executes first Micro or Macro ?
Question 68. How will the code execute(testing Micro and Macro)?
Question 69. Can we schedule a MicroTask Manually ?
Question 70. Are Micro and Macro Task synch or Async ?
Question 71. Explain Webworker ?
Question 72. How to create WebWorker ?
Question 73. What are postmessage and onmessage in webworker ?
Question 74. Can Webworker update UI ?
Question 75. WebWorker vs Async Task
Question 76. WebWorker vs Promises
Question 77. Asynch vs Threads
Question 78. Concurrency vs Parallelism