How to Write single proc for all operations?

Have you looked at the MERGE command? That allows you to pass data through a single statement and then conditionally insert, update or delete as needed. Here's the MSDN entry: http://msdn.microsoft.com/en-us/library/bb510625.aspx

Thank you all for replies!!! I got the answer from my friend!!!

CREATE PROCEDURE spForAllOperations
 @StudentID INT ,
 @SName CHAR(20) ,
 @SAddress CHAR(40) ,
 @PresentClassID INT ,
 @SubjectID INT ,
 @SMarks INT ,
 @Flag INT
 AS 
 IF @Flag = 1 -- @Flag=1 Inserting the Compltely new record into the database tables
 BEGIN

 INSERT  INTO Student
 VALUES  ( @StudentID, @SName, @SAddress )

 INSERT  INTO Student_Marks
 VALUES  ( @StudentID, @PresentClassID, @SubjectID, @SMarks )

 END

 ELSE 
 IF @Flag = 2 --- @Flag=2Inserting the already existing record of the student
 BEGIN

 INSERT  INTO Student_Marks
 VALUES  ( @StudentID, @PresentClassID, @SubjectID, @SMarks )

 END

 ELSE 
 IF @Flag = 3 --- @Flag=3 Updating the Marks and Address of the Student
 BEGIN

 UPDATE  Student
 SET     Address = @SAddress
 WHERE   Stud_Id = @StudentID

 UPDATE  Student_Marks
 SET     Marks = @SMarks
 WHERE   Subject_Id = @SubjectID
 AND Class_Id = @PresentClassID
 AND Stud_Id = @StudentID

 END

In this way I will pass all the variables from my VB6 application with an extra reference to Flag . So If that condition satisfies then the action will perform otherwise don't. In this way We can write only one Stored proc for all the operations.