C# : To Connect to a MySql Database

Things Needed:
You should have installed MySQL and MySQL Connector/NET. You can download installers from http://dev.mysql.com/downloads
Microsoft Visual C# or Visual Studio.
To use the methods in the MySQL Connector/NET you should add a reference to it. Right click your project in the Solution Explorer and click Add Reference… In the .NET tab, chose MySql.Data and click ok.

       
  
using System;
using MySql.Data.MySqlClient;

public class Example
    {

    static void Main()
        {
       
        String str = @"server=localhost;database=project;userid=root;password=;";
        MySqlConnection con = null;
        try
            {
            con = new MySqlConnection(str);
            con.Open(); //open the connection
            Console.Write("Sucess");
            }
        catch (MySqlException err) //We will capture and display any MySql errors that will occur
            {
            Console.WriteLine("Error: " + err.ToString());
            }
        finally
            {
            if (con != null)
                {
                con.Close(); //safely close the connection
                }
            }
        Console.ReadLine();
        }
    }

       
 

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Top C# Interview Questions

1. What is C#?

C# is an object oriented, type safe and managed language that is compiled by .Net framework to generate Microsoft Intermediate Language.

2. What are the types of comment in C# with examples?

Single line      //This is a Single line comment

/*This is a multiple line comment We are in line 2 Last line of comment*/

/// summary; ///  Set error message for multilingual language. /// summary

3. Can multiple catch blocks be executed?

No, Multiple catch blocks can’t be executed. Once the proper catch code executed, the control is transferred to the finally block and then the code that follows the finally block gets executed.

4. What is the difference between public, static and void?

Public declared variables or methods are accessible anywhere in the application. Static declared variables or methods are globally accessible without creating an instance of the class. The compiler stores the address of the method as the entry point and uses this information to begin execution before any objects are created. And Void is a type modifier that states that the method or variable does not return any value.

5. What is an object?  

An object is an instance of a class through which we access the methods of that class. “New” keyword is used to create an object. A class that creates an object in memory will contain the information about the methods, variables and behavior of that class.

6. Define Constructors?  

A constructor is a member function in a class that has the same name as its class. The constructor is automatically invoked whenever an object class is created. It constructs the values of data members while initializing the class.

7. What is Jagged Arrays?

The array which has elements of type array is called jagged array. The elements can be of different dimensions and sizes. We can also call jagged array as Array of arrays.

8. What is the difference between ref & out parameters?

An argument passed as ref must be initialized before passing to the method whereas out parameter needs not to be initialized before passing to a method.

9. What is the use of using statement in C#?  

The using block is used to obtain a resource and use it and then automatically dispose of when the execution of block completed.

10. What is serialization?  

When we want to transport an object through network then we have to convert the object into a stream of bytes. The process of converting an object into a stream of bytes is called Serialization. For an object to be serializable, it should inherit ISerialize Interface.
De-serialization is the reverse process of creating an object from a stream of bytes.

11. Can “this” be used within a static method?  

We can’t use ‘This’ in a static method because we can only use static variables/methods in a static method.

12. What is difference between constants and read-only?  

Constant variables are declared and initialized at compile time. The value can’t be changed after wards. Read-only variables will be initialized only from the Static constructor of the class. Read only is used only when we want to assign the value at run time.

13. What is an interface class?  

Interface is an abstract class which has only public abstract methods and the methods only have the declaration and not the definition. These abstract methods must be implemented in the inherited classes.

14. What are value types and reference types?  

Value types are stored in the Stack whereas reference types stored on heap.
Value types:

1	int, enum , byte, decimal, double, float, long

Reference Types:

1	string , class, interface, object

15. What are Custom Control and User Control?  

Custom Controls are controls generated as compiled code (Dlls), those are easier to use and can be added to toolbox. Developers can drag and drop controls to their web forms. Attributes can be set at design time. We can easily add custom controls to Multiple Applications (If Shared Dlls), If they are private then we can copy to dll to bin directory of web application and then add reference and can use them.
User Controls are very much similar to ASP include files, and are easy to create. User controls can’t be placed in the toolbox and dragged – dropped from it. They have their design and code behind. The file extension for user controls is ascx.

16. What are sealed classes in C#?  

We create sealed classes when we want to restrict the class to be inherited. Sealed modifier used to prevent derivation from a class. If we forcefully specify a sealed class as base class then a compile-time error occurs.

17. What is method overloading?  

Method overloading is creating multiple methods with the same name with unique signatures in the same class. When we compile, the compiler uses overload resolution to determine the specific method to be invoke.

18. What is the difference between Array and Arraylist?  

In an array, we can have items of the same type only. The size of the array is fixed. An arraylist is similar to an array but it doesn’t have a fixed size.

19. Can a private virtual method be overridden?  

No, because they are not accessible outside the class.

20. Describe the accessibility modifier “protected internal”.

Protected Internal variables/methods are accessible within the same assembly and also from the classes that are derived from this parent class.

21. What are the differences between System.String and System.Text.StringBuilder classes?

System.String is immutable. When we modify the value of a string variable then a new memory is allocated to the new value and the previous memory allocation released. System.StringBuilder was designed to have concept of a mutable string where a variety of operations can be performed without allocation separate memory location for the modified string.

22. What’s the difference between the System.Array.CopyTo() and System.Array.Clone() ?

Using Clone() method, we creates a new array object containing all the elements in the original array and using CopyTo() method, all the elements of existing array copies into another existing array. Both the methods perform a shallow copy.

23. How can we sort the elements of the array in descending order?

Using Sort() methods followed by Reverse() method.

24. Write down the C# syntax to catch exception?

To catch an exception, we use try catch blocks. Catch block can have parameter of system.Exception type.


Another 

1.  What is object-oriented programming (OOP) Language?
Object-oriented programming (OOP) is a programming language model organized around objects rather than "actions" and data rather than logic. Historically, a program has been viewed as a logical procedure that takes input data, processes it, and produces output data.

2. Explain about C# Language.
C# is a OOPs language, .net framework use to compiled it, to generate machine code.

3. Types of comments in C#?

Single line comments
// for single line comments

Multiple line comments
/* for multi line comments */

XML tags comments

/// XML tags displayed in a code comment


4. Top reason to use C# language?
 Modern, general-purpose programming language
Object oriented.
Component oriented.
Easy to learn.
Structured language.
It produces efficient programs.
It can be compiled on a variety of computer platforms.
Part of .Net Framework.

5. feature of C# language?
Boolean Conditions
Automatic Garbage Collection
Standard Library
Assembly Versioning
Properties and Events
Delegates and Events Management
Easy-to-use Generics
Indexers
Conditional Compilation
Simple Multithreading
LINQ and Lambda Expressions
Integration with Windows

6. What is a Class?
a set or category of things having some property or attribute in common and differentiated from others by kind, type, or quality.

7. What is object?
Objects are created from Classes, in C#, is an instance of a class that is created dynamically. Object is also a keyword that is an alias for the predefined type System.

8. What is Constructors, explain with syntax 
A is special method of the class that will be automatically invoked when an instance of the class is created is called as constructor.

Constructors are mainly used to initialize private fields of the class while creating an instance for the class.

When you are not creating a constructor in the class, then compiler will automatically create a default constructor in the class that initializes all numeric fields in the class to zero and all string and object fields to null.

Syntax.
[Access Modifier] ClassName([Parameters])
{
}

9. Types of Constructors
Basically constructors are 5 types those are
Default Constructor
Parameterized Constructor
Copy Constructor
Static Constructor
Private Constructor

10. index value of the first element in an array?
first element is 0 (zero). In a Array.

11. Different between method overriding and  method overloading?
In Overriding methods it will create two or more methods with same name and same parameter in different classes.

while Overloading it will create more then one method with same name but different parameter in same class.

12. Explain use of Abstract and Sealed Classes in C#?
The abstract keyword enables you to create classes and class members that are incomplete and must be implemented in a derived class.

The sealed keyword enables you to prevent the inheritance of a class or certain class members that were previously marked virtual.

13. What is Static Classes?
A static class is basically the same as a non-static class, but there is one difference: a static class cannot be instantiated.
In other words, you cannot use the new keyword to create a variable of the class type. Because there is no instance variable, you access the members of a static class by using the class name itself.

14. Explain Static Class Members.
A non-static class can contain static methods, fields, properties, or events.

The static member is callable on a class even when no instance of the class has been created. The static member is always accessed by the class name, not the instance name. Only one copy of a static member exists, regardless of how many instances of the class are created.

Static methods and properties cannot access non-static fields and events in their containing type, and they cannot access an instance variable of any object unless it is explicitly passed in a method parameter.

15. Which are Access Modifiers available in C#?
All types and type members have an accessibility level, which controls whether they can be used from other code in your assembly or other assemblies.

You can use the following access modifiers to specify the accessibility of a type or member when you declare it:
public: The type or member can be accessed by any other code in the same assembly or another assembly that references it.
private: The type or member can be accessed only by code in the same class or struct.
protected: The type or member can be accessed only by code in the same class or struct, or in a class that is derived from that class.
internal: The type or member can be accessed by any code in the same assembly, but not from another assembly.

16. Data Types in C#?
bool, byte , char, decimal , double, float, int, long, sbyte , short, uint, ulong, ushort.

More question coming soon.. we are updating our list of ques and answer... :)
keep wait and watch for few days.

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Top SEO Interview Questions

1) What is SEO and introduce its types?

Search engine optimization or SEO is a process of keep changing the position of a web page or website in a search engine results by using keywords or phrases.

Two Types of SEO are:

On Page Optimization
Off Page Optimization

2) What are the SEO tools do you use?

The SEO tools that I use are Google analytic, keyword search, Alexa, open site explorer, Google Webmaster.

3) What do you mean by Backlink?

 The incoming links to your website or webpage is referred as Backlink.

4) What are out bound Links?

The outbound links are our website links to other webpage or website.

5) Can you tell me something about Googlebot?

To index a webpage Google uses the Googlebot software. Caching, Crawling and indexing of a webpage are done through Googlebot by collecting details from that webpage.

Seo

6) What is Cross linking and what are the function of Cross linking?

Cross linking is used to refer the process of linking one site to another site and provide a way to allow the accessing to it.
It provides the users with reference sites that consists the content related to the search.
It doesn’t need to be owned by the same person as it provides the methods that have been built on the Internet.
It serves the purpose to display the page on the search engines using search engine optimization techniques and methods.
The site ranking is calculated on the basis of the relevance of the sites and then it is reflected on the search engine.
It uses SEO tools that provide reciprocal links and inbound links that can be used as our SEO.
7) What is the main purpose of using keyword in SEO?

Keyword is a single word, and while a combination of those keywords makes phrases. These keywords or phrases are used by the search engines to populate the subjects over the internet. Search engine stores keywords in the database, and when search is done, it will come up with the best possible match.

8) Can you mention the functions of body content relevance?

Whenever there is a text that does not have images on the web page is referred as body content relevance or non-image text. It helps in good optimization of the sites and also to improve your ranking in the search engine.

9) What are Spiders, Robots and Crawlers and what are their functions?

Spiders, robot and crawler, they are all same and referred by different names. It is a software program that follows, or “Crawls” different links throughout the internet, and then grabs the content from the sites and adds to the search engine indexes.

10) What does it mean if nothing appears on doing search on the domain?

On doing search on your domain and if nothing appears then there are three possibilities.

May be the site is banned by search engines
May be no index by search engines
Some canonical issues
11)What is keyword stemming?

The process of finding out the root word from the search query is referred as keywords stemming.

12) Name some SEO blogs that you frequently read?

Jimboykins
Search Engine Land
SEOSmarty
MOZ
Search Engine Journal
13) What do you mean by Cloaking?

Cloaking is a deceptive way of optimizing search. In this technique a different content will be searched by the search engine than what is presented or searched by the users.

14) How many types of Meta Tags are there in SEO and what are their characters limits?

There are two types Meta tags in SEO.

Description Meta tag with 150 characters limits
Keyword Meta tag with 200 characters limits
15) How many characters limits in Title tag?

We can add 70 characters in title tag.

16) What is Google Sandbox?

Google sandbox is an imaginary area where new websites and their search rating are put on hold until they prove worthy for ranking. In other words, it checks the standard of the website.

17) Tell me something about Black Hat SEO?

In order to get a high ranking in search engine result page, websites go for various methods and techniques which are characterized by two categories. One method that is acceptable by search engine guidelines is known as White Hat SEO, while the other method which is not acceptable by search engine guidelines is known as Black Hat SEO.

18) Name few Black Hat SEO techniques?

Link Farming
Hidden text, etc.
Gateway or Doorway pages
Cloaking
Keyword Stuffing
19) Can you differentiate between ‘nofollow’ and ‘dofollow’ link?

Nofollow links are not passed by search engines bot and therefore cannot be cached or indexed. Dofollow link is a kind of hyperlink and it passes through all search engines and it puts an impact over page rank.

20) What is the difference between PR (page rank) and SERP (Search engine result page)?



Page rank is calculated on the basis of quality inbound links from other website or webpages to our webpage or a website.

SERP (Search Engine Result page) is the placement of the website or web-pages which is returned by the search engine after a search query or attribute.

21) Why the Title Tag in website is valuable?

Title tags are very essential in SEO, as it tells about the contents on that web page. Through title tags only the search engine will tell the user, what is there in the page.

22) What is considered as more significant, creating content or building backlinks?

Both are necessary, creating quality content is equally important to building backlinks. Although, building backlinks are useful in building authority to a site and for ranking as well, quality content is the first element that is considered to be more responsible for ranking.

23) Can you mention the difference between SEO and SEM?

SEM (Search Engine Marketing), it is used for the promotion of website through Search Engine Result Page (SERP) , while to optimize the search result of your webpage or website SEO (Search Engine Optimization) is used.

24) What do you know about LSI?

LSI stands for Latent Semantic Indexing. This technique is established to obtain the data by relating the word to its closest counterparts or to its similar context. For example, if you are searching something with a keyword “CAR” it will show all the related things like classic cars, car auctions, Bentley car, car race etc.

25) How will you cross-check whether your SEO campaign is working or not?

To check whether your SEO campaign is working or not, the first approach is to check the websites statistics, which tells you about the origin of traffic.  The other way of checking is to make a search based on the relevant keywords and key phrases and look for the search result. The number of search result will tell you whether your SEO campaign is working or not.

26) What is the meaning of competitive analysis?

Competitive analysis does the comparison, between the website I am optimizing, and the website that is ranked highly in search results.

27) What will be your next steps if your SEO methods or technique does not work?

My first attempt would to try analysis the problem and resolve them step by step

Firstly I would try to see whether it is a new project, and then like to re-check the key words.
Also, I would look for relevant key-words that can be helpful.
Even though the webpage and website has been indexed well and still not appearing on the first 10 pages of search engine result page, then I would make some changes in page text, titles and description.
If website is not indexed well or dropped from the index, than it might comprises     serious issues and re-work might be required.
28) What is PPC?

PPC stands for Pay Per Click and is an advertisement campaign hosted by Google.  It is segmented into two modules CPC ( Cost per click) and CPM ( Cost per thousand impressions) through flat rate and bidding respectively. In CPC, if the user clicks on the advert, only then the advertiser will be charged.

29) What is 301 redirect?

It is a method by which the user is redirected to new page url to old page url . It is a permanent redirect and it is also useful in directing link juice to new url from old url .

30) What are Webmaster tools?

Webmaster tool is a service provided by Google from where you can get backlink information, crawl errors, search queries, Indexing data, CTR etc.

31) What is keyword density and what is the formula for knowing keyword density?

From SEO point of view, keyword density will definitely help to stand out your content from others. The formula to know the keyword density is ( Total number of keyword/ total number of words in your article) multiply by 100.

32) What is robots.txt?

Robots.txt is a text file. It is through this file, it gives instruction to search engine crawlers about indexing and caching of a webpage, file of a website or directory, domain.

33) What will you do, for the company website you are working for, decides to move all the contents to new domain?

The first step would be to update the previous site with a permanent redirect to new page for all the pages. After that, I will remove the previous content from search engine in order to avoid duplicate content issues.

34) Can you optimize the website which has pages in millions?

From SEO point of view, for dynamic website, special additional SEO stuffs have to be    implemented.

Good Internal link structure
Generation of dynamic title and description
Dynamic XML sitemap generation
35) What is the latest update in SEO?

The latest updates in SEO are:

Panda
Penguin
Bonus! 3 More!

36) What are the key aspects of Panda update?

Panda is to improve the search in Google. The latest version has focused on quality content, proper design, proper speed, proper use of images and many more.

37) What are the key aspects of Penguin update?

Penguin is the code name for Google algorithm. Its main target is to decrease the ranking of that website that are violating the Google Webmaster guidelines. These guidelines are violated by using black hat techniques like cloaking and stuffing.

38) How will you neutralize a toxic link to your site?
Through Backlink Quality Checker you can know who links to your website. Now, you have to go to ‘ Toxic link’ report, where you will find all the links, that are harmful to your websites. If there is any link in ‘ Toxic link report’ that matches with the link on your website, then you can remove it by using ‘Google Disavov tool’.

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Top JSON Interview Questions

1) Mention what is JSON?

JSON is a simple data exchange format.  JSON means JavaScript Object Notation; it is language and platform independent.

2) Explain what is JSON objects?

An object can be defined as an unordered set of name/value pairs.  An object in JSON starts with {left brace} and finish or ends with {right brace}.  Every name is followed by: (colon) and the name/value pairs are parted by, (comma).

3) Explain how to transform JSON text to a JavaScript object?

One of the common use of JSON is to collect JSON data from a web server as a file or HTTP request, and convert the JSON data to a JavaScript, ant then it avails the data in a web page.

4) Mention what is the rule for JSON syntax rules? Give an example of JSON object?

JSON syntax is a set of the JavaScript object notation syntax.

Data is in name/value pairs
Data is separated by comma
Curly brackets hold objects
Square bracket holds arrays

5) Why must one use JSON over XML?

It is faster and lighter than XML as on the wire data format
XML data is typeless while JSON objects are typed
JSON types: Number, Array, Boolean, String
XML data are all string
Data is readily available as JSON object is in your JavaScript
Fetching values is as simple as reading from an object property in your JavaScript code
json-logo

6) Mention what is JSON-RPC and JSON Parser?

JSON RPC: It is a simple remote procedure call protocol same as XML-RPC although it uses the lightweight JSON format instead of XML
JSON Parser: JSON parser is used to parse the JSON data into objects to use its value. It can be parsed by javaScript, PHP and jQuery
7) Mention what is the file extension of JSON?

File extension of JSON is .json

8) Mention which function is used to convert a JSON text into an object?

To convert JSON text into an object “eval” function is used.

9) Mention what are the data types supported by JSON?

Data types supported by JSON includes

Number
String
Boolean
Array
Object
Null

10) Mention what is the role of JSON.stringify?

JSON.stringify() converts an object into a JSON text and saves that JSON text in a string.



11) Show how to parse JSON in JQuery?

To parse JSON in JQuery, we will see the example

var json = ‘{“name”: “Guru 99”, “Description “: “Learn PHP Interactively with PHP Beginner Tutorials}

obj = $.parseJSON(json);

//alert(obj.name);

12) Mention what is the function used for encoding JSON in PHP?

For encoding JSON in PHP, json_encode () function is used.  This function returns the JSON representation of a value on success or false on failure.

13) Explain how you can convert a string into a JSON Array?

To convert a string into a JSON array, you need to create a JSONObject object for each of your objects, and add those to your JSON array.

14) Mention what are the JSON files?

JSON file type for JSON files is “.json”
The MIME type for JSON text is “application/json”
15) List out the uses of JSON?

Uses of JSON includes

When writing application based on JavaScript it uses JSON, which includes browser extension and websites
JSON is used for transmitting and serializing structured data over network connection
JSON is mainly used to transfer data between server and web application
Web service and API’s use JSON format to provide public data
JSON can be used with modern programming language
16) Mention what are the drawbacks of JSON?

Drawbacks of json are

It does not contain type definition
It lacks some sort of DTD
17) Mention what is the MIME type of JSON?

MIME type for JSON text is “application/json”

18) Mention what is JSONP?

JSONP stands for JSON with padding. It is a method used to bypass the cross-domain policies in web browsers. In other words, JSONP is the simple way to deal with browser restrictions when sending JSON responses from different domains from the client.

19) Mention what is the difference between JSON and JSONP?

JSON: JSON is a simple data format used for communication medium between different systems
JSONP: It is a methodology for using that format with cross domain ajax requests while not being affected by same origin policy issue.

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