Some Question and Answer - Chapter 1

1. Difference between clustered index and non-clustered index.
Clustered Index
Stored table’s data physically in disk location.
One table can have one clustered index.
Required no separate storage.
Table with clustered index called clustered table. Its rows are stored in a B-Tree structured.
Table without any clustered index called non-clustered table. Rows stored in a Heap structure unsorted.
Primary key creates clustered index by default.
Non-Clustered Index
Stored separately table data into disk location.
One table can have multiple non-clustered index.
One table can have multiple non-clustered index.
Required separate storage to store the index information

2. Purpose of Global.asax
Global.asax allow you to write code that runs in response of system level events, like
Application_Start, Application_End, Session_Start, Session_End, Application_BeginRequest, Application_AuthenticateRequest, Application_Error.
It is also useful to declare global variable.

using System;
using System.Data;
using System.Linq;
using System.Web;

/// <summary>
/// Contains my site's global variables.
/// </summary>
public static class Global
{
   /// <summary>
   /// Global variable storing important stuff.
   /// </summary>
   static string _importantData;

   /// <summary>
   /// Get or set the static important data.
   /// </summary>
   public static string ImportantData
   {
get
{
   return _importantData;
}
set
{
   _importantData = value;
}
   }
}
3. Global variable
In global.asax as static. This variable can be accessible from all the session that is currently connected with that particular application, and as it is static, all application can access a single instance of that variable. Example of usages: for no of logged in user count or no of hit count till now.

4. If cookies is turned off in browser window how system manages session.
If the cookies are disabled in the middle of a user's session, that session will be lost on a subsequent request.

If you were using cookie session mode, asp.net will issue a special cookie named ASP.NET_SessionId, which contains the Session ID. Each time the user sends a request, the browser sends this cookie as part of the Request Cookie collection. If that cookie is not present, asp.net thinks that this is a completely new session, so it will start a new session and issue a new Session ID cookie. Again on the subsequent requests, since asp.net will not find the previously issued Session ID cookie, it will start a new session again.. This goes on and on.

If you are using cookie-less session then it is maintaining the session id within URL in encrypted.
5. Practical uses of interface
6. Difference in SQL 2008 vs 2012
2008
Supports 1000 partitions.
Used 27 bit precision for spatial.
String function CONCATE & FORMAT not available.
2012
Supports 15000 partitions.
Used 48 bit precision for spatial.
CONCATE & FORMAT two new function available.

7. Disadvantage of normalization
Advantage:
Overcome for data redundancy.
Less effort for index.
Disadvantage:
Required to join every time to fetch data value, sometimes it takes higher time for worst case query and huge data.

8. Disadvantage of server.transfer
• Server.Transfer can be used only to transfer within the pages of the same web applications, but we can use Response.Redirect to move to any page available over the Internet.
• Response.Redirect sends message to the browser saying it to move to some different page, while Server.Transfer does not send any message to the browser but rather redirects the user directly from the server itself.
• With Server.Transfer you can preserve your information using preserveForm property. Response.Redirect lose access to all of the properties in the Request object.
• Response.Redirect requires a round trip. Whereas, Server.Transfer does not requires a round trip. Means we can’t user query string.

9. Security between node to router
Most common attacks are
• SQL injection -- mitigate with parameters
• Cross site scripting  -- mitigate by HTML encoding all untrusted values
• Cross site request forgery -- mitigate by using a anti forgery token
• Clickjacking -- mitigate with X-Frame-Options HTTP header

10. What is Webservice
A Web service is a method of communication between two electronic devices over a network. It is a software function provided at a network address over the Web with the service always on as in the concept of utility computing. The W3C defines a Web service generally as.
Web Services
• Web services are application components
• Web services communicate using open protocols
• Web services are self-contained and self-describing
• Web services can be discovered using UDDI
• Web services can be used by other applications
• HTTP and XML is the basis for Web services
11. Difference between Website and WebApplication.
Website:
Web sites are typically informational in nature with a limited amount of advanced functionality. A web site usually refers to the front-end interface through which the public interacts with a business online.
Web applications:
A Rich Internet Applications (RIA), are presented as either a web site or as part of a web site, but not all web sites are web applications. A web application is a web site that DOES something other than display content to the masses. It’s intended for user interactions and transactions, performing actual business functions, and not simply displaying information to a user.

12. Application pools
Application pools are used to separate set of IIS worker process that share the same configuration and application boundaries. It provides us isolation our web app for better security, reliability, availability and performance and keep running without impacting each other.

13. Protocol
A set of rules governing the format of data sent over the internet or other network.

14. SSL
SSL stands for secure socket layer, means it is technology to establish an encrypted connection between server and client, typically a web-client means browser and, or webserver or mail server.

15. Hosting – SSL IP only
Remove port 80 access first, then system only can access with SSL. But still it is accessible with IP address. Now edit SSL certification binding section in IIS. Write host name in specific text box. This will restrict the host name only to access with SSL.

16. DOM
The Document Object Model (DOM) is an application programming interface (API) for valid HTML and well-formed XML, SVG Documents. It defines logical structure of documents (a tree) and a way to access the structure from programming (for change the structure, style and content).

17. API
API stands for application programming interface, is a set of routines, protocols, and tools of building software applications. API express a component in terms of inputs, outputs, and underlying types.

18. Hosting types supported by WCF
• Hosting in internet service (IIS)
• Hosting in windows activation service (WAS)
• Hosting in a console or Desktop application (self-hosting)
• Hosting in a widows service
www.codeproject.com/Articles/550796/A-Beginners-Tutorial-on-How-to-Host-a-WCF-Service
rahulrajatsingh.com/

19. Windows Service
A service is an application almost like other. A service can run in background, even no one is logged on to the system. Service didn’t have any user interface. Reduce overhead of server.
Some other management command like start, stop, pause, continue. Also be able to handle server events such as shutdown.
For install and uninstall please see www.c-sharpcorner.com/UploadFile/8f2b4a/how-to-installuninstall-net-windows-service-C-Sharp/