SQL Questions and Answers

What is SQL?
SQL stands for Structured Query Language. It is a special-purpose programming language designed for managing data in relational database management systems (RDBMS). Most popular SQL commands are "Select", "Insert", "Update", and "Delete".

What is RDBMS?
RDBMS stands for Relational Database Management System. It is a database management system (DBMS) that is based on the relational model as introduced by E. F. Codd, of IBM's San Jose Research Laboratory. Many popular databases such as IBM DB2, MySQL, Microsoft SQL, Oracle currently in use are based on the relational database model.

What is database normalization?
Database normalization is the process of organizing the fields and tables of a relational database to minimize redundancy and dependency. Normalization usually involves dividing large tables into smaller (and less redundant) tables and defining relationships between them. (http://en.wikipedia.org/wiki/Database_normalization)

What is a primary key?  
A primary key is a single field or combination of fields that uniquely defines a record. Primary key can not contain a null value. A table can have only one primary key.

What is a stored procedure?
A stored procedure is a group of Transact-SQL statements compiled into a single execution plan.

What is a trigger? 
A database trigger is a special stored procedure that is automatically executed in response to certain events on a particular table or view in a database. The trigger is mostly used for maintaining the integrity of the information on the database.
Related posts:
SQL Questions and Answers – Part 3
SQL Questions and Answers – Part 2
SQL Questions and Answers – Part 1

ASP.NET Questions and Answers

What is ASP.NET?
ASP.NET is a Web platform that provides all the services that you require to build enterprise-class server-based Web applications. ASP.NET is built on the .NET Framework, so all .NET Framework features are available to ASP.NET applications. Your applications can be written in any language that is compatible with the common language runtime (CLR), including Visual Basic and C#.
Source:  http://msdn.microsoft.com/en-us/library/dd566231%28v=vs.100%29.aspx

ASP.NET is a unified Web development model that includes the services necessary for you to build enterprise-class Web applications with a minimum of coding. ASP.NET is part of the .NET Framework, and when coding ASP.NET applications you have access to classes in the .NET Framework. You can code your applications in any language compatible with the common language runtime (CLR), including Microsoft Visual Basic and C#. These languages enable you to develop ASP.NET applications that benefit from the common language runtime, type safety, inheritance, and so on.
Source: http://msdn.microsoft.com/en-us/library/4w3ex9c2%28v=vs.100%29.aspx

What is a Cookie?
A cookie, also known as an HTTP cookie, web cookie, or browser cookie, is usually a small piece of data sent from a website and stored in a user's web browser while a user is browsing a website. When the user browses the same website in the future, the data stored in the cookie can be retrieved by the website to notify the website of the user's previous activity. Cookies were designed to be a reliable mechanism for websites to remember the state of the website or activity the user had taken in the past.
Source: http://en.wikipedia.org/wiki/HTTP_cookie

Describe the complete ASP.NET page lifecycle.

1. Page request: The page request occurs before the page life cycle begins. When the page is requested by a user, ASP.NET determines whether the page needs to be parsed and compiled (therefore beginning the life of a page), or whether a cached version of the page can be sent in response without running the page.
2. Start: In the start stage, page properties such as Request and Response are set. At this stage, the page also determines whether the request is a postback or a new request and sets the IsPostBack property. The page also sets the UICulture property.
3. Initialization: During page initialization, controls on the page are available and each control's UniqueID property is set. A master page and themes are also applied to the page if applicable. If the current request is a postback, the postback data has not yet been loaded and control property values have not been restored to the values from view state.
4. Load: During load, if the current request is a postback, control properties are loaded with information recovered from view state and control state.
5. Postback event handling: If the request is a postback, control event handlers are called. After that, the Validate method of all validator controls is called, which sets the IsValid property of individual validator controls and of the page. (There is an exception to this sequence: the handler for the event that caused validation is called after validation.)
6. Rendering: Before rendering, view state is saved for the page and all controls. During the rendering stage, the page calls the Render method for each control, providing a text writer that writes its output to the OutputStream object of the page's Response property.
7. Unload: The Unload event is raised after the page has been fully rendered, sent to the client, and is ready to be discarded. At this point, page properties such as Response and Request are unloaded and cleanup is performed.

Source: MSDN - ASP.NET Page Life Cycle Overview

Related posts:

• ASP.NET Questions and Answers – Part 5
• ASP.NET Questions and Answers – Part 4
• ASP.NET Questions and Answers – Part 3
• ASP.NET Questions and Answers – Part 2
• ASP.NET Questions and Answers

New Year New Password

Your password should change frequently. If you cannot change every month, every quarter, then at least once a year.

When you change the password, it should NOT in "The 25 worst passwords of 2012". You should NOT using the same password for all accounts. Use the KeePass or a password protected LibreOffice document to keep track your password. Read "The guide to password security (and why you should care)" for more info.

Happy New Year!

Beware of Fake Federal Express Emails

When I maintained my client's computer few days ago, I found his computer infected by trojan downloader Win32/Kuluoz.B

These trojans infected my client's computer since he clicked on the fake email claimed from Federal Express.

As a matter of fact, the delivery companies like Federal Express, UPS, DHL and US Post Office never send email notification. They don't know your email. If they cannot delivery package, they will left a note at your door.

It took me an hour to clean up and re-scan whole computer to make sure it clean. So, beware when you check email.

Microsoft Exam 70-480: Programming in HTML5 with JavaScript and CSS3

I passed the Microsoft Exam 70-480 Programming in HTML5 with JavaScript and CSS today. I am so happy. I took this exam for FREE! using this voucher code: HTMLJMP (voucher code available through 3/31/2013 or while supplies last). In the past few months, I spent sometime to learn and using HTML5, CSS3, JavaScript and JQuery. Here are some resources I used to learn:

• Dive Into HTML5 by Mark Pilgrim with contributions from the community
• Microsoft Virtual Academy: Developing in HTML5 with JavaScript and CSS3 Jump Start
• Microsoft Channel 9: HTML5 & CSS3 Fundamentals: Development for Absolute Beginners
• Microsoft Channel 9: Javascript Fundamentals: Development for Absolute Beginners
• HTML5 Rocks - A resource for open web HTML5 developers
• W3.org: HTML5: Edition for Web Authors 
• Mozilla Developer Network: HTML5
• Microsoft:  Internet Explorer 10 Guide for Developers (Windows)
• CSS Font-Size: em vs. px vs. pt vs. percent | Kyle Schaeffer - Web Design and SharePoint Branding
• W3Schools.com:  HTML5 Introduction
• TechExams.net: 70-480 - Programming in HTML5 with JavaScript and CSS3
• Free video lession from Lynda.com: CSS, HTML5 

How to Open the HTML File in Plain Text Mode Using TextEdit

Open the HTML file using TextEdit in Mac/OS will render it in the rich text format by defaut. If you would like to view the HTML tags or edit it by typing your own HTML statements, you need to open it in plain text format. To open in plain text form:

1. Click on Preferences
2. Select the Open and Save
3. Click on 'Ignore rich text commands in HTML files

 This is why many developers prefer to use gedit from GNOME as a text editor

Visual Studio 2010 Keyboard Shortcuts

These keyboard shortcuts are helpful. Some of them are not document in Visual Studio 2010 Express, for example:
<Ctrl> F5 to run the application without debug
<Ctrl> Period or <Ctrl> Space for code completion.
<Ctr> <Shift> <B> to build the solution

For more download the Visual Studio 2010 Keybinding Posters from Microsoft.

Credit: Visual Studio 2010 Keyboard Shortcuts - ScottGu's Blog

DevCurry: 30 Favorite Visual Studio Keyboard Shortcuts