CLR function SQL 2005

SQL 2005 provides an amazing option of writing c# code and deploying the dll in the SQL Server which will be processed there itself.
We can make use of the usual ADO.Net coding here.

While creating the DataBase project itself, you will be prompted to establish the SQL connection. To use the same connection within the .cs file included in the project, use this.

SqlConnection con = new SqlConnection("context connection=true")

To connect to an external source the PermissionLevel should be set to 'External' in the Database tab of the project properties. If it is 'safe', it will not allow to access an external server other than the one mentioned in the connectionstring of the project.

SqlConnection con = new SqlConnection("datasource=servername;inital catalog=DB name;user id=user;password=pwd;")

Having done with the coding, just select the 'Deploy solution' in the build menu and the function will be deployed in the DB.
For the 'External' property to work the DB in which the dll is going to be deployed should have

'trustworthy' property set ON.

The Connectionstring in the project property refers to the server in which our CLR function will be deployed. The function will be deployed in the 'Functions' folder present under 'Programmability' of the DataBase. The compiled dll is placed under the Assembly folder.

By Turning trustworthy property ON in the DB, any remote script can tamper the DB. Since this will lead to security threat, we can sign the dll generated with the certificate, enable the remote access and deploy it. Let me make a separate post regarding this procedure.

Swapping of Integer values using XOR(c#)

With reference to,this post the title seem to be one of the frequently asked Interview questions.

Initially I was bit puzzled on how XOR works with swapping Integer values. Did a bit of recollection in "Digital Systems" and got the clue.

To know how the result is determined using XOR logic refer here

Let me go with the same example in the post referred.

int intNumOne = 9,
int intNumTwo = 1;

//Swapping of numbers starts here

intNumOne ^= intNumTwo;
intNumTwo ^= intNumOne;
intNumOne ^= intNumTwo;
Response.Write("Value of First Variable :: " + intNumOne.ToString() + "");
Response.Write("Value of Second Variable :: " + intNumTwo.ToString() + "");

Convert the number as binary and apply XOR rule.

intNumOne ^= intNumTwo:
intNumOne = 9 = 1001
intNumTwo =1 = 0001
-------
intNumOne = 1000 (Applying the XOR rule)
-------
Decimal equivalent of 1000 is 8.

intNumTwo ^= intNumOne:

intNumTwo = intNumTwo ^ intNumOne = 1^8 = 9

intNumOne = intNumOne^ intNumTwo =8 ^9 = 1

Swapping Result:
intNumOne = 1
intNumTwo =9