Dynamically Creating Computed Columns in SQL

If you are into programming you should have definitely worked with calculated fields in SQL. But for others I will briefly explain what they are.

Calculated columns are columns which depend on other columns. It gets its value by calculating which can involve values of other columns. The calculation formula is the only thing stored in the column.

So each time the column is referenced the calculation is done. But if you use the keyword “persisted” while creating the column then the values will be kept in the table. Whenever a referenced value is updated the computed column is also automatically updated to highlight the change. Also by using persisted you can index a computed column.

You can create a table with persisted computed column as follows.

1. CREATE TABLE Customer
2. (
3. CustomerId INT IDENTITY(1, 1) NOT NULL,
4. CustomerFirstName NVARCHAR(100) NOT NULL,
5. CustomerLastName NVARCHAR(100) NOT NULL,
6. CustomerFullName AS CustomerFirstName + ' ' + CustomerLastName PERSISTED
7. )

One thing to remember is that you cannot directly insert values to a computed column.

I think you got a basic idea of computed columns. Now I would like to show how to create a computed column dynamically. For example think that you need to add a computed column to a table using a stored procedure. It is not a big deal.

I need to insert a TotalOrder column to the table named FoodOrder.

1. CREATE TABLE FoodOrder
2. (
3. OrderId INT IDENTITY(1, 1) NOT NULL,
4. OrderDate SMALLDATETIME NULL,
5. CustomerName NVARCHAR(100) NOT NULL,
6. TotalStarter INT NULL,
7. TotalMainCourse INT NULL,
8. TotalSoftBevarage INT NULL,
9. TotalLiquer INT NULL,
10. TotalDessert INT NULL
11. )

This can be done using the following query.

1. DECLARE @sExecuteCommand VARCHAR(250), --Keepa the command to be executed.
2. @sColumns VARCHAR(150) --Keeps the columns to be included in the formula.
3.  
4. SET @sColumns = 'TotalStarter+TotalMainCourse+TotalSoftBevarage+TotalLiquer+TotalDessert+'
5. SET @sExecuteCommand = 'ALTER TABLE FoodOrder ADD TotalOrder AS ' + SUBSTRING(@sColumns, 1, LEN(@sColumns)-1) -- Creating the computed column.
6. EXEC (@sExecuteCommand)

Note that a cursor or a loop can be easily used to populate the variable “sColumns” with the columns required for the formula.

Hope this helps.

UPDATE with JOIN

If you need to update data of a table (DestinationTable) with data of another table (SourceTable) there are 3 ways you can get this done in SQL.

Method 1

This is the most common and simple way with using a sub query.

1. UPDATE DestinationTable SET DestinationColumn =
2.     (SELECT ValueColumn FROM SourceTable WHERE DestinationTable.MappingColumn = SourceTable.MappingColumn)

 

Method 2

This users the most common FROM clause to join the two tables as shown below.

1. UPDATE DestinationTable SET DestinationColumn = SourceTable.ValueColumn
2. FROM SourceTable
3. WHERE DestinationTable.MappingColumn = SourceTable.MappingColumn

 

Method 3

Last method mentioned below uses the join clause to join both the tables to make the update happen properly.

1. UPDATE DestinationTable SET DestinationColumn = SourceTable.ValueColumn
2. FROM DestinationTable
3. INNER JOIN SourceTable ON DestinationTable.MappingColumn = SourceTable.MappingColumn

 

Hope these helps.

Naracoorte Caves – Naracoorte South Australia

If you are a cave lover, there are many places Australia has to offer. Out of them one of the best is Naracoorte caves in South Australia. Inside the caves you will be able to see lime stones which took about 200 million years to form.

Stalactites – Are the ones hanging from above. Because they form from water dripping from above they tend to get points on them.

 

Stalagmites – Are formed on floor and start growing up with time.

Columns – Are formed by one stalactite and stalagmite connecting after so many years.

 

It is good idea to plan and visit the caves bit early since you need time to have a look into the caves. They normally close at 5PM and the last tour starts around 4PM.

There is a visitor information centre in the Wonambi Fossil Centre so you can find out the interesting places in Naracoorte Caves National Park. Wet cave is a free attraction. When you purchase a ticket for a tour to visit Alexandra cave you will get free admittance to the Fossil enter and the miniature man made zoo.

Pram accessibility is not there when visiting caves, also you need to take care of your young children because they might need lot of assistance from you when inside the caves. Also supervise your children frequently since some of the Stalactites and Stalagmites are fragile and if they break one then thy may be destroying millions of years of natures’ work.

Car parking is free and plenty of sitting areas are there. Toilet facilities are there also is a restaurant so you can buy food if you need.

Address : Naracoorte Caves National Park, PO Box 134, Naracoorte SA 5271.

Phone : (+61 8) 8762 2340

EMail : naracoortecaves@sa.gov.au

Web : http://www.environment.sa.gov.au/naracoorte/Home

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Deep Creek Conservation Park, South Australia

If you would love to enjoy scenery and wild life, a place you should definitely visit is Deep Creek conservation park in South Australia. It is located at the southern tip of the Fleurieu Peninsula.

It is always better to have a 4WD or an AWD but with a 2WD also in good weather you will be able to do most of the tracks without any major problems.

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Rocking Horse – Gumeracha South Australia

When you come to South Australia another good place you should visit is the Rocking Horse at Gumeracha. There you will find a huge wooden rocking horse to which you can climb after paying few dollars. You can also watch the birds kept there and do not forget the Toy Factory nearby to do some shopping which has a good collection of gifts.

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If any one interested visiting below are the contact details. But do not try to rock the horse.

Address
The Toy Factory,
Adelaide-Mannum Road,
Gumeracha, SA 5233,
South Australia,
Australia.

Telephone
(08) 8389 1085

Map

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Developing iPhone and Android Applications using C# .Net

Being a .Net developer did you think how great if you could develop applications for most popular mobile device platforms like iPhone and Android with the .Net skills you already have. If you were thinking like me then the wait is over.

Now with Mono you can create cross platform applications using your .Net framework skills. Mono is a software platform using which you can develop applications which runs on iPhones, Android devices, iPads and iPod Touches.

As per the Mono site, “The Mono Project is an open development initiative sponsored by Novell to develop an open source, UNIX version of the Microsoft .NET development platform.” If you are wondering about the name Mono, it is 'monkey' in Spanish.

You can try Mono for free by downloading the trial by going to the trial link. The good thing is after installing Mono you can use the more familiar Visual Studio to do the development using the available Mono templates.

Whispering Wall – Williamstown South Australia

Barossa Dam or whispering wall in Williamstown is not a place you should miss in your visit to South Australia. From the outer look it is just a dam created in Barossa Reservoir. But the magic starts after you send a friend to the other side of the dam and speak.

You and your friend will be able to talk as you two are near each other. The sound is very clear hence the name you can whisper and that will be heard by a person who is in the other side of the dam.

I was said that when the dam was built the lead engineer used to listen to the workers using this amazing facility to get to know what they are talking about him. Also it seems a later attempt to build a similar dam following the same design and material failed to demonstrate the whisper ability. So this is a unique dam you will not find elsewhere.

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Adelaide – South Australia

Thought to share some nice photos captured in the city I live in. Even though the city is small there are many thing that you can enjoy in this city so I recommend Adelaide for travelers. If you are in Australia don’t forget to visit Adelaide for few days.

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Album contain photos of Adelaide city and few of the many gardens Adelaide.

Cathedral shown is the famous St. Peters Cathedral located in 27, King William Road, Adelaide, SA 5000, Australia. Which is located in the following map.

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Expandable Regions using HTML

You can create nice looking expandable regions using just HTML and some Java scripting. This is specially useful if you are to create a site without any major programming languages. Today I thought to share an expandable region that I created to give you an idea to get it done.

When the code works it will look like the following.

You should be excited by now, to get it working you need the following code inserted into a body section of a HTML file. Please note I have added the CSS also in to the page body, but if you have a separate CSS file please separate the CSS .

1. <style type="text/css">
2.     a.headingStyle
3.     {
4.         text-decoration: none;
5.         margin-left: 0.5em;            
6.     }
7.     a.headingStyle:hover
8.     {
9.         text-decoration: underline;
10.     }
11.     a.headingStyle span.charStyle
12.     {
13.         font-family: monospace;
14.         font-weight: normal;
15.     }
16.     .contentStyle
17.     {
18.         display: none;
19.         margin-left: 1.5em;
20.         margin-right: 0.5em;
21.         margin-bottom: 0.5em;
22.         border-width: thin;
23.         border-style: outset;
24.         background-color:#D2E3FF;
25.     }
26.     .upArrowStyle
27.     {
28.         height:32px;
29.         background-image: url('Up_Arrow_32x32.png');
30.         background-repeat:no-repeat;
31.     }
32.     .downArrowStyle
33.     {
34.         height:32px;
35.         background-image: url('Down_Arrow_32x32.png');
36.         background-repeat:no-repeat;
37.     }
38. </style>
39.  
40. <script type="text/javascript">
41.     function display(item) {
42.         if (document.getElementById) {
43.             // Retrieving the first child item.
44.             var firstChildItem = item.firstChild;
45.             // Getting the correct child item with inner HTML text.
46.             firstChildItem = item.firstChild.innerHTML ? item.firstChild : item.firstChild.nextSibling;
47.             // Toggling the + or - according to the state after click.
48.             firstChildItem.innerHTML = firstChildItem.innerHTML == '+' ? '-' : '+';
49.             // Toggling the display image after click.
50.             item.className = item.className == "downArrowStyle" ? "upArrowStyle" : "downArrowStyle";
51.             // Get the sub item to toggle visibility.
52.            var nextSubItem = item.parentNode.nextSibling.style ? item.parentNode.nextSibling : item.parentNode.nextSibling.nextSibling;
53.             // Toggle visibility of the sub item.
54.             nextSubItem.style.display = nextSubItem.style.display == 'block' ? 'none' : 'block';
55.         }
56.     }
57.  
58.     // Displaying everything if item could not be found.
59.     if (!document.getElementById)
60.         document.write('<style type="text/css"><!--\n .dspcont{display:block;}\n //--></style>');
61. </script>
62.  
63. <!-- If Java scripts are blocked, display everything expanded. -->
64. <noscript>
65.     <style type="text/css">
66.         .dspcont
67.         {
68.             display: block;
69.         }
70.     </style>
71. </noscript>
72. <div>
73.     <!-- If + or - is required to be displayed besides the image simply change display:none; to display:block; in following sections. -->
74.     <h1>
75.         <a href="javascript:void(0)" class="downArrowStyle" onclick="display(this)">
76.             <span style="display:none;">+</span><span style="margin-left:34px;">Main Title 1</span>
77.         </a>
78.     </h1>
79.     <div class="contentStyle">Title 1 content goes here.</div>
80.     <h1>
81.         <a href="javascript:void(0)" class="downArrowStyle" onclick="display(this)">
82.             <span style="display:none;">+</span><span style="margin-left:34px;">Main Title 2</span>
83.         </a>
84.     </h1>
85.     <div class="contentStyle">
86.         <h2>
87.             <a href="javascript:void(0)" class="downArrowStyle" onclick="display(this)">
88.             <span style="display:none;">+</span><span style="margin-left:34px;">Sub Title 1</span></a></h2>
89.         <div class="contentStyle">
90.             Sub title 1 content goes here.</div>
91.         <h2>
92.             <a href="javascript:void(0)" class="downArrowStyle" onclick="display(this)">
93.             <span style="display:none;">+</span><span style="margin-left:34px;">Sub Title 2</span></a></h2>
94.         <div class="contentStyle">
95.             Sub title 2 content goes here.</div>
96.     </div>
97.     <h1>
98.         <a href="javascript:void(0)" class="downArrowStyle" onclick="display(this)">
99.         <span style="display:none;">+</span><span style="margin-left:34px;">Main Title 3</span></a></h1>
100.     <div class="contentStyle">Title 3 content goes here.</div>
101. </div>

 

Remember to correct the image URLs, otherwise they will go missing.

I need to thank M. C. Matti for his great article which gave me this idea. Also you can use this method to create expandable regions in other sites which use different technologies. For example if you need to add this to a SharePoint site, just use a Content Editor web part and paste the code using Source Editor in web part properties.

Hope this helps.

HTML Menu

Today I thought to share with you, how to create menus using HTML only. These menus will be very useful if you need to create web sites using only HTML.

Above menu is created using basic unordered list (UL), list items (LI), links and some CSS.

Below is the HTML code for the menu. In the code I have created the full menu using HTML lists and used CSS to format the list to work as a menu.

1. <ul class="mainMenu">
2.     <li class="mainMenuItem"><a href="Home.html" class="mainMenuLink">Home</a>
3.         <ul class="subMenu">
4.             <li class="subMenuItem"><a href="Page1.html" class="subMenuItemLink">e</a></li>
5.             <li class="subMenuItem"><a href="Page2.html" class="subMenuItemLink">ee</a></li>
6.         </ul>
7.     </li>
8.     <li class="mainMenuItem"><a href="Module1.html" class="mainMenuLink">Module 1</a>
9.         <ul class="subMenu">
10.             <li class="subMenuItem"><a href="Module1_Page1.html" class="subMenuItemLink">dd</a></li>
11.             <li class="subMenuItem"><a href="Module1_Page2.html" class="subMenuItemLink">ddd</a></li>
12.             <li class="subMenuItem"><a href="Module1_Page3.html" class="subMenuItemLink">dddd</a></li>
13.         </ul>
14.     </li>
15.     <li class="mainMenuItem"><a href="Module2.html" class="mainMenuLink">Module 2</a>
16.         <ul class="subMenu">
17.             <li class="subMenuItem"><a href="Module2_Page1.html" class="subMenuItemLink">c</a></li>
18.             <li class="subMenuItem"><a href="Module2_Page2.html" class="subMenuItemLink">cc</a></li>
19.             <li class="subMenuItem"><a href="Module2_Page3.html" class="subMenuItemLink">ccc</a></li>
20.         </ul>
21.     </li>
22.     <li class="mainMenuItem"><a href="Module3.html" class="mainMenuLink">Module 3</a>
23.         <ul class="subMenu">
24.             <li class="subMenuItem"><a href="Module3_Page1.html" class="subMenuItemLink">bb</a></li>
25.             <li class="subMenuItem"><a href="Module3_Page2.html" class="subMenuItemLink">bbb</a></li>
26.             <li class="subMenuItem"><a href="Module3_Page3.html" class="subMenuItemLink">bbbb</a></li>
27.         </ul>
28.     </li>
29.     <li class="mainMenuItem"><a href="Module4.html" class="mainMenuLink">Module 4</a>
30.         <ul class="subMenu">
31.             <li class="subMenuItem"><a href="Module4_Page1.html" class="subMenuItemLink">aa</a></li>
32.             <li class="subMenuItem"><a href="Module4_Page2.html" class="subMenuItemLink">aaa</a></li>
33.             <li class="subMenuItem"><a href="Module4_Page3.html" class="subMenuItemLink">aaaa</a></li>
34.         </ul>
35.     </li>
36. </ul>

 

Below is the CSS that you need to make the above HTML work as a menu.

1. .subMenu
2. {
3.     padding: 1px;
4.     position: absolute;
5.     visibility: hidden;
6. }
7. .subMenuItem
8. {
9.     list-style: none;
10.     float: left;
11.     position: relative;
12.     margin: 0px;
13.     display: block;
14.     width: 92px;
15. }
16. .subMenuItemLink
17. {
18.     color: White;
19.     text-align: left;
20.     text-decoration: none;
21.     padding-left: 5px;
22.     display: block;
23.     height: 32px;
24.     width: 92px;
25.     background-image: url('./Images/menuButtonSelected.jpg');
26. }
27. <!-- Changing the menu when mouse is over the menu. -->
28. .mainMenuItem:hover .mainMenuLink
29. {
30.     color: White;
31.     background-color: Blue;
32.     background-image: url('./Images/menuButtonSelected.jpg');
33. }
34. <!-- Changing the menu when it is selected. -->
35. .mainMenuItem:active .mainMenuLink
36. {
37.     background-image: url('./Images/menuButtonSelected.jpg');
38. }
39. <!-- Showing the sub menu items when mouse is over the main menu. -->
40. .mainMenuItem:hover .subMenu
41. {
42.     visibility: visible;
43.     z-index: 100;
44. }

 

Do not forget to import the CSS into the HTML page by using a link as shown below.

1. <link rel="stylesheet" type="text/css" href="DefaultStyles.css" />

 

I used the following images as the background images of the links.

 

I think the code is not that complex, so hope this helps, let me know if you need any help on this, I will try to help you out.

Microsoft Flight

In early 2009 I got shocked when I heard that Microsoft Aces game studio was closed down by Microsoft which was responsible for developing well known PC simulation software's and games such as Flight Simulator, Combat Flight Simulator and Train Simulator.

But recently after getting to know that Microsoft is now developing the Flight Simulator internal at Microsoft I am more than happy. After seeing the new visuals of the renamed product Microsoft Flight, I am extremely exited and waiting until they release the next version.

See for your selves by visiting Microsoft Flight site which is the next version of Microsoft Flight Simulator X.

Word Field Code Samples

As I mentioned in my last post, I will list down some uses of Word field codes here. If you would like to know what they are I invite you to read my previous post on field codes.

Notes -

• Always remember to user Ctrl + F9 to put curly braces, sorry no copy pasting, you have to type all.
• If the codes are misbehaving, right click and click on Update Field.

1. Using Word how to greet the user according to the time of the day.

 

{ If "{ Time \@ "HH:mm" }" > "12:00" { If "{ Time \@ "HH:mm" }" > "15:00" { If "{ Time \@ "HH:mm" }" > "18:00" "Good Night" "Good Evening" } "Good Afternoon" } "Good Morning" }

2. Concatenating text and displaying in Word.

Welcome { UserName } you are reading { FileName \* MergeFormat }.

3. Displaying page number in odd pages and text on others in Word.

{ If { =Mod({ Page }, 2) } =1 { Page } "PTO" }

4. Using Word skipping page number on first two pages and then showing page numbers starting from number 2.

{ If { Page } < 3 "" { ={ Page } - 1 } }

5. Displaying last saved user name on the last page in Word.

{ If { Page } = { NumPages } "This { FileName } was last saved by { LastSavedBy } on {DocProperty LastSavedTime }. Document was edited for { EditTime } minutes." "" }

6. Displaying number of characters, words, paragraphs, pages in a Word document.

This document has { NumWords } words in { NumPages } pages.

This document has { NumChars } characters in { DocProperty Paragraphs } paragraphs.