Difference between DML DDL DCL and TCL?

DML:

DML is abbreviation of Data manipulation Language. It is useed to work with the data of the tables.

Basic Statements: SELECT, UPDATE, INSERT, delete statements.

DateTime Functions

To get current date

SELECT GETDATE()

To get yesterday

SELECT DATEADD(d,-1,GETDATE())

Saving changes is not permitted in SQL 2008 Management Studio?

I recently started using SQL Server 2008, at first it was really nice, but then I started getting a weird error every time I tried modifying a table.

"Saving changes is not permitted. The changes you have made require the following tables to be dropped and re-created. You have either made changes to a table that can’t be re-created or enabled the option Prevent saving changes that require the table to be re-created."

Row Data Bound Event and how to use it

Row Data Bound Event and how to use it :


Control Used :Grid View 
Event Under Grid View :onrowdatabound

Error 'System.Web.UI.WebControls.GridView' does not have a public property named 'SortedAscendingCellStyle'.

Parser Error

Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately. 

Parser Error Message: Type 'System.Web.UI.WebControls.GridView' does not have a public property named 'SortedAscendingCellStyle'.

Source Error: 

Line 91: <RowStyle BackColor="White" ForeColor="#003399" />
 Line 92: <SelectedRowStyle BackColor="#009999" Font-Bold="True" ForeColor="#CCFF99" />
 Line 93: <SortedAscendingCellStyle BackColor="#EDF6F6" />
 Line 94: <SortedAscendingHeaderStyle BackColor="#0D4AC4" />
 Line 95: <SortedDescendingCellStyle BackColor="#D6DFDF" />

Intermittent Invalid Viewstate Error in ASP.NET Web pages

Error:
The issue presents itself with and error similar to this:
c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\mdcr\5c7639a0\5981344d\App_Web_oja12imh.0.cs Line: 0 

Stack Trace: 


[FormatException: Invalid character in a Base-64 string.]
System.Convert.FromBase64String(String s) +0
System.Web.UI.ObjectStateFormatter.Deserialize(String inputString) +77
System.Web.UI.ObjectStateFormatter.System.Web.UI.IStateFormatter.Deserialize(String serializedState) +4
System.Web.UI.Util.DeserializeWithAssert(IStateFormatter formatter, String serializedState) +37
System.Web.UI.HiddenFieldPageStatePersister.Load() +113




[ViewStateException: Invalid viewstate. 
Client IP: known ip
Port: Port number XX
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.04506.648; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; InfoPath.3; .NET4.0C; .NET4.0E)
ViewState: 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...]


Cause : 
There are many reasons for this error :

1. Web Farm or server cluster.
2. Form Posts
3. Application pool recycling 
4. Proxy servers and virus scanners

Resolution :

1. Use specific machine key in your web config. we can use these tools Link 1 or Link 2. Sample Key Node:
   
   <machineKey validationKey=”56AB7132992003EE87F74AE4D9675D65EED8018D3528C0B8874905B51940DEAF6B85F1D922D19AB8F69781B2326A2F978A064708822FD8C54ED74CADF8592E17″
   decryptionKey=”A69D80B92A16DFE1698DFE86D4CED630FA56D7C1661C8D05744449889B88E8DC”
   validation=”SHA1″ decryption=”AES”
   />
2. Post to the same aspx page.
3. Turn off the firewall and antivirus software.
4. Adjust the settings on the application pools so that recycling is less likely to occur at peak periods.

How to remove all asp.net data cache by c#

Introduction :
Cache feature is a great feature in asp.net. By caching we store data in memory for quick access. As Microsoft eloquently puts it, "Caching is a technique widely used in computing to increase performance by keeping frequently accessed or expensive data in memory. In the context of a Web application, caching is used to retain pages or data across HTTP requests and reuse them without the expense of recreating them."

But many times we want to update our cache for new updates to happen so to remove data cache from memory. the code snippet given below can be used to remove data cache from memory :

Method One :

foreach (DictionaryEntry dCache in HttpContext.Current.Cache)

{

   HttpContext.Current.Cache.Remove(dCache.Key.ToString());

}

Method Two :

IDictionaryEnumerator cacheEnumerator = HttpContext.Current.Cache.GetEnumerator();

while (cacheEnumerator.MoveNext())

{

  HttpContext.Current.Cache.Remove(cacheEnumerator.Key.ToString());

}

We need these two namespaces to perform this task as Generics is used

using System.Collections;
using System.Collections.Generic;


Conclusion:
These methods are used to remove data cache from memory it won't remove other cache like output or others .....