Finding Number of Records in SQL Tables

By using the following query you will be able to get all the tables with at least one record in the selected database. It will be handy when you needed to get an idea of the number of records in a database. This uses two SQL Server system views, namely SysObjects and SysIndexes.

1. SELECT sysobjects.name AS [Table Name],
2.         MAX(sysindexes.rows) AS [Number of Records],
3.         sysobjects.crdate AS [Created Date],
4.         sysobjects.refdate AS [Referenced Date]
5. FROM sysobjects
6. INNER JOIN sysindexes ON sysobjects.id = sysindexes.id
7. WHERE sysobjects.xtype = ‘U’ — Filtering all the User Tables.
8.     AND sysindexes.rows > 0 — Getting all the tables having at least one reoord.
9. GROUP BY sysobjects.name,
10.     sysobjects.crdate,
11.     sysobjects.refdate
12. ORDER BY 2 DESC — Ordering by the number of records in table.

 

Above query will bring the following results on the Northwind database.

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HTTP Error 404.13 – Not Found – The request filtering module is configured to deny a request that exceeds the request content length.

I recently got this error in one of my applications. When troubleshooting, I found my application is configured to have the default value of 30000000 Bytes for the content length, which was not sufficient for me in some of the file uploading functionalities.

Simply adding / increasing the number in the configuration file corrected this error.

Request Content Length in Bytes.

Default Value – 30000000 Bytes (~28MB)

Maximum Value – 4284229877 Bytes (3.99GB)

1. <system.webServer>
2.   <security>
3.     <requestFiltering>
4.       <requestLimits maxAllowedContentLength=“100000000“></requestLimits>
5.     </requestFiltering>
6.   </security>
7.   …
8. </system.webServer>

 

To obtain more information read this article.

SQL Truncate vs. Delete

By now as you know, in this post I am going to discuss about two SQL commands we use regularly to clear data in our tables.

Usage

1. DELETE FROM TABLENAME
3. TRUNCATE TABLE TABLENAME

Even though they do a similar thing, there are some differences which makes them unique commands.

	DELETE	TRUNCATE
1.	Considered as Data Mining Language (DML) statement.	Considered as Data Definition Language (DDL) statement.
2.	Can be used to delete all or part of data in a table.	Will delete all the data in a table.
3.	Will log the actions.	There will be no logging on record deletion.
4.	Will use more locks.	Will use fewer locks.
5.	Will use more resources.	Will use less resources.
6.	Slow.	Fast.
7.	Will not reset the identity seed.	Will reset the identity seed to 0.
8.	Can be used to delete data in tables having relationships.	Cannot use in tables having relationships.
9.	Can be used in tables involved in log shipping or replication.	Cannot be used in tables involved in log shipping or replication.
10.	Transaction can be rolled back.	No rollback.
11.	Table may keep the empty pages. Can be released by running, SHRINKDATABASE (Database Name).	Data pages related to the table will be de allocated and returned to the system.
12.	Related Triggers are fired.	Triggers are not fired.

 

If you used DELETE to fully remove all the records, you can reset the identity value by running the following command.

1. DBCC CHECKIDENT (TABLENAME, RESEED, 0)

If you do have some rows left in table, simply replace 0 with the last identity column value. For example if you put 5 instead of 0 then the next record inserted into the table will have an identity column value of 6.

If you jus need to check the current identity value just use the following command.

1. DBCC CHECKIDENT (TABLENAME, NORESEED)

Importing Data into SQL

If you need to import data from a file, this can be achieved by using SQL Bulk Insert command. Recently I did use this method to import some 500 000 data from few comma separated value (CSV) files and thought to share it with you. What you need to remember is, if you are importing data from more than one file the data should have the same format through out the files.

This is a sample set of data I imported into my table from the file named File1.csv.

Login,Name,Date,Result,Pass

U0001,Roman Silva,1/10/2010 17:23,100,TRUE

U0002,Anthony Don,28/09/2010 10:01,70,TRUE

U0003,Saman Perera,16/09/2010 11:31,90,TRUE

U0004,Silvia Raz,26/09/2010 22:11,40,FALSE

U0005,Rebecca Maine,18/09/2010 11:30,100,TRUE

I used the following script to create a temporary table for my imported data.

1. SET ANSI_NULLS ON
2. GO
3.  
4. SET QUOTED_IDENTIFIER ON
5. GO
6.  
7. CREATE TABLE [dbo].[TABLENAME_ImportedData](
8.     [LoginId] [NVARCHAR](50) NOT NULL,
9.     [Name] [NVARCHAR](200) NULL,
10.     [Date] [DATETIME] NULL,
11.     [Result] [INT] NULL,
12.     [Pass] [NVARCHAR](8) NULL
13. ) ON [PRIMARY]
14.  
15. GO

To fetch data from the file I used the following script.

1. BULK INSERT [TABLENAME_ImportedData]
2. FROM 'D:\DataFiles\File1.csv'
3. WITH (
4.          FIELDTERMINATOR =',', — Since my columns are seperated using commas (,).
5.          ROWTERMINATOR ='\n',  — Since each data row is in its own line.
6.          FIRSTROW = 2          — Since my first row is having column names. Please note FIRSTROW is not recommended to skip the column names.
7.       )

While running the script I faced an issue with the date since my server was set to US English as the default language. In US English the dates should be in MDY format. So I had 3 choices, either to change the date formats on my data files, change the server default language to another language which has its date format as DMY or change the date format of the server. I used the easy way to change the date format of the server by running the following command.

1. SET DATEFORMAT dmy

If you like to change SQL server default language and need help please read my article on that.

Changing SQL Server Default Language

If you needed to change the default language of a SQL Server login you can do so by using sp_defaultlanguage command.

First determine the current default language by using the @@language variable as follows.

1. SELECT @@language

Then choose the language you want to change to from the available languages. You can find the available languages by the following command.

1. EXEC sys.sp_helplanguage

After selecting the language wanted to change, run the following command to change the default language, I am changing it to British using the following command.

1. DECLARE @Login NVARCHAR(30)
2. SET @Login = SYSTEM_USER
3. EXEC sp_defaultlanguage @Login, 'British'

Run the @@language to see whether the default language is changed as you wanted. Do not forget to use a new query window to see the changes.

Handler was not added through the Sys.UI.DomEvent.addHandler method.

Sometime back I started getting this error in all the forms in which AJAX tools were used. The thing worried me most is that there were no changes made to the project source code. Later a friend of mine found that it is happening because of the wrong AjaxControlToolkit.

As I feel this dll swap happens when a control is dragged from the Visual Studio toolbox because the toolbox is referenced to a newer version of the toolkit than the project was using.

If you are also getting this error simply delete all the AJAX related files and folders in your projects’ bin directory. Once you are done there should not be any folders such as ar, cs, de, etc. Also remove the AjaxControlToolkit.dll. Then copy the version of the toolkit dll your project was using earlier to the Bin directory. Now clean and build your project to see the error disappear.

If you are still getting the error after correctly doing all this you might be getting the error due to another reason causing the same error. Since there are many reasons for this same error you better check the internet for other reasons to find out the exact reason causing the error for you.

Correcting AJAX Calendar Extender Popup Calendar Position

Recently I encountered a positioning error in AJAX calendar extender. When I use the calendar extender inside of other container controls the popup calendar started appearing few inches above the button. You will be able to get an idea of the problem by the following image.

Since I couldn’t get it fixed by changing the properties I thought to find a solution for this.

One way to correct this is by applying a CSS style sheet to change the calendar positioning manually. I found this method while searching the web. This way since you need to enter the location of the calendar you need to try several times to get the correct positioning. If you are using this method simply place the following CSS style in your page and apply the style as shown. Remember you need to change the value to suit your form.

1. <style type="text/css">
2.     .fromDtPos
3.     {
4.         left: 245px !important;
5.     }
6. </style>

Apply the style to your calendar extender.

1. <cc2:calendarextender id="calExpiry" runat="server" targetcontrolid="txtExpiry"
2.     format="dd MMM yyyy" popupbuttonid="imgExpiry" enabled="True" cssclass="ajax__calendar fromDtPos">
3. </cc2:calendarextender>

My preferred way to do this is by using the JavaScript that I wrote below. Since you do not need to enter the position manually this will be easier. Also this code will work irrespective of the number of parent containers it is having above of the control.

Insert the below JavaScript into your page.

1. <script type="text/javascript" language="javascript">
2.     function showCalendar(sender, args) {
3.         var processingControl = $get(sender._button.id); // Getting the control which triggered the calendar.
4.         sender._popupDiv.parentElement.style.top = processingControl.offsetTop + processingControl.height + ‘px’;
5.         sender._popupDiv.parentElement.style.left = processingControl.offsetLeft + ‘px’;
6.  
7.         var positionTop = processingControl.height + processingControl.offsetTop;
8.         var positionLeft = processingControl.offsetLeft;
9.         var processingParent;
10.         var continueLoop = false;
11.  
12.         do {
13.             // If the control has parents continue loop.
14.             if (processingControl.offsetParent != null) {
15.                 processingParent = processingControl.offsetParent;
16.                 positionTop += processingParent.offsetTop;
17.                 positionLeft += processingParent.offsetLeft;
18.                 processingControl = processingParent;
19.                 continueLoop = true;
20.             }
21.             else {
22.                 continueLoop = false;
23.             }
24.         } while (continueLoop);
25.  
26.         sender._popupDiv.parentElement.style.top = positionTop + ‘px’;
27.         sender._popupDiv.parentElement.style.left = positionLeft + ‘px’;
28.     }
29. </script>

Then call the function showCalendar on onClientShown event of the calendar extender as seen below.

1. <cc2:calendarextender id="calExpiry" runat="server" targetcontrolid="txtExpiry"
2.     format="dd MMM yyyy" popupbuttonid="imgExpiry" enabled="True" onclientshown="showCalendar">
3. </cc2:calendarextender>

Both of the above methods will correct the appearance of the popup calendar of the AJAX Calendar Extender as seen below.

HTTP Error 500.19 – Internal Server Error

Recently in one of my machines I got the above HTTP error when running an application hosted on IIS 7. The detailed error was as below.

“This configuration section cannot be used at this path. This happens when the section is locked at a parent level. Locking is either by default (overrideModeDefault="Deny"), or set explicitly by a location tag with overrideMode="Deny" or the legacy allowOverride="false".”

After doing some troubleshooting I was managed to get this error fixed by reinstalling ASP.Net by running the aspnet_regiis –ir command.

For more information on running the command please refer to my old article Unable to start debugging on the web server.

Styles missing in CalendarExtender

When you put an Ajax Calendar Extender inside of a GridView you will see the calendar without any styling on it meaning the calendar will show only the dates overlapping with other items on your form. Sometimes some dates might even be missing. See the sample appearances below.

This happens because the style sheets are not loaded at the correct time due to a bug in toolkit, there are several ways to fix this.

One is to add another calendar extender outside of the update panel and keep it hidden.

Another is to disable partial rendering in the script manager. But this will slow down your site reducing the benefits gained from AJAX.

1. <asp:ScriptManager ID="ScriptManager1" EnablePartialRendering="false" runat="server">
2. </asp:ScriptManager>

My chosen method is to add the styles manually to the style sheet. To move forward this way simply copy the following styles which are used by the calendar extender to your style sheet.

1. .ajax__calendar_container {padding:4px;cursor:default;width:170px;font-size:11px;text-align:center;font-family:tahoma,verdana,helvetica;}
2. .ajax__calendar_body {height:139px;width:170px;position:relative;overflow:hidden;margin:auto;}
3. .ajax__calendar_days, .ajax__calendar_months, .ajax__calendar_years {top:0px;left:0px;height:139px;width:170px;position:absolute;text-align:center;margin:auto;}
4. .ajax__calendar_container TABLE {padding:0px;margin:0px;font-size:11px;}
5. .ajax__calendar_container TD {padding:0px;margin:0px;font-size:11px;}
6. .ajax__calendar_header {height:20px;width:100%;}
7. .ajax__calendar_prev {cursor:pointer;width:15px;height:15px;float:left;background-repeat:no-repeat;background-position:50% 50%;background-image:url(../images/arrow-left.gif);}
8. .ajax__calendar_next {cursor:pointer;width:15px;height:15px;float:right;background-repeat:no-repeat;background-position:50% 50%;background-image:url(../images/arrow-right.gif);}
9. .ajax__calendar_title {cursor:pointer;font-weight:bold; margin-left:15px; margin-right:15px;}
10. .ajax__calendar_footer {height:15px;}
11. .ajax__calendar_today {cursor:pointer;padding-top:3px;}
12. .ajax__calendar_dayname {height:17px;width:17px;text-align:right;padding:0 2px;}
13. .ajax__calendar_day {height:17px;width:18px;text-align:right;padding:0 2px;cursor:pointer;}
14. .ajax__calendar_month {height:44px;width:40px;text-align:center;cursor:pointer;overflow:hidden;}
15. .ajax__calendar_year {height:44px;width:40px;text-align:center;cursor:pointer;overflow:hidden;}
16.  
17. .ajax__calendar .ajax__calendar_container {border:1px solid #646464;background-color:#ffffff;color:#000000;}
18. .ajax__calendar .ajax__calendar_footer {border-top:1px solid #f5f5f5;}
19. .ajax__calendar .ajax__calendar_dayname {border-bottom:1px solid #f5f5f5;}
20. .ajax__calendar .ajax__calendar_day {border:1px solid #ffffff;}
21. .ajax__calendar .ajax__calendar_month {border:1px solid #ffffff;}
22. .ajax__calendar .ajax__calendar_year {border:1px solid #ffffff;}
23.  
24. .ajax__calendar .ajax__calendar_active .ajax__calendar_day {background-color:#edf9ff;border-color:#0066cc;color:#0066cc;}
25. .ajax__calendar .ajax__calendar_active .ajax__calendar_month {background-color:#edf9ff;border-color:#0066cc;color:#0066cc;}
26. .ajax__calendar .ajax__calendar_active .ajax__calendar_year {background-color:#edf9ff;border-color:#0066cc;color:#0066cc;}
27.  
28. .ajax__calendar .ajax__calendar_today .ajax__calendar_day {border-color:#0066cc;}
29. .ajax__calendar .ajax__calendar_today .ajax__calendar_month {border-color:#0066cc;}
30. .ajax__calendar .ajax__calendar_today .ajax__calendar_year {border-color:#0066cc;}
31.  
32. .ajax__calendar .ajax__calendar_other .ajax__calendar_day {background-color:#ffffff;border-color:#ffffff;color:#646464;}
33. .ajax__calendar .ajax__calendar_other .ajax__calendar_year {background-color:#ffffff;border-color:#ffffff;color:#646464;}
34.  
35. .ajax__calendar .ajax__calendar_hover .ajax__calendar_day {background-color:#edf9ff;border-color:#daf2fc;color:#0066cc;}
36. .ajax__calendar .ajax__calendar_hover .ajax__calendar_month {background-color:#edf9ff;border-color:#daf2fc;color:#0066cc;}
37. .ajax__calendar .ajax__calendar_hover .ajax__calendar_year {background-color:#edf9ff;border-color:#daf2fc;color:#0066cc;}
38.  
39. .ajax__calendar .ajax__calendar_hover .ajax__calendar_title {color:#0066cc;}
40. .ajax__calendar .ajax__calendar_hover .ajax__calendar_today {color:#0066cc;}
41.  
42. /* styles for invalid dates as defined by startDate and endDate*/
43. .ajax__calendar .ajax__calendar_invalid .ajax__calendar_day {background-color:#ffffff;border-color:#ffffff; color:#646464; text-decoration:line-through; cursor:default;}
44. .ajax__calendar .ajax__calendar_invalid .ajax__calendar_month {background-color:#ffffff;border-color:#ffffff; color:#646464; text-decoration:line-through; cursor:default;}
45. .ajax__calendar .ajax__calendar_invalid .ajax__calendar_year {background-color:#ffffff;border-color:#ffffff; color:#646464; text-decoration:line-through; cursor:default;}
46.   .ajax__calendar .ajax__calendar_invalid .ajax__calendar_today{visibility:hidden; cursor:default;}

Note that the above CSS uses the “arrow-left.gif” and “arrow-right.gif” for the previous and next buttons. If you want, you can use any other image which suits you. In case you need the originals they are below. To correctly show the previous and next buttons you need to place these images on to the “Images” folder under your project. If the folder is different in your project please change the image paths in the above CSS.

• arrow-left.gif –
• arrow-right.gif –

After doing all this remember to link the style sheet to your web page.

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

If you have done everything correctly your calendar will be shown properly while residing inside of the grid.

Reloading a Page using JavaScript

Ways to reload a page using Java script.

When doing web development if you need to reload / refresh a page using Java script, you can use one of the following three methods.

1. <script language="javascript" type="text/javascript">
2.     function ReloadMethod1() {
3.         window.location.href = window.location.href;
4.     }
5.     function ReloadMethod2() {
6.         window.location.reload();
7.     }
8.     function ReloadMethod3() {
9.         history.go(0);
10.     }
11. </script>
12. <input type="button" value="Reload" onclick="window.location.href=window.location.href" />
13. <%–Calling Javascript function on button click.–%>
14. <input type="button" value="Reload" onclick="ReloadMethod2()" />
15. <input type="button" value="Reload" onclick="window.location.reload()" />
16.  
17. <!– ASP Buttons –>
18. <asp:Button ID="Button1" runat="server" Text="Reload" OnClientClick="window.location.href=window.location.href" />
19. <%–Calling Javascript function on button click.–%>
20. <asp:Button ID="Button2" runat="server" Text="Reload" OnClientClick="ReloadMethod2()" />
21. <asp:Button ID="Button3" runat="server" Text="Reload" OnClientClick="ReloadMethod3()" />