Question

I had a stored procedure which has to be input with more than 8000 rows at a single button click that is used to close the daily attendance of employees.

I plan to send the input to stored procedure as datatable rather than sending it as row by row each time

I managed to create a table type user-defined type and used a parameter with that user-defined type as input parameter

  USE [ATCHRM.MDF]
GO

/****** Object:  UserDefinedTableType [dbo].[employeeswipedclose123]    Script Date: 12/11/2012 12:04:34 ******/
CREATE TYPE [dbo].[employeeswipedclose123] AS TABLE(
    [empid] [int] NULL,
    [datetoday] [datetime] NULL,
    [Swipepk] [int] NULL
)
GO
  CREATE PROCEDURE dbo.CloseAttendance (@closingemployee dbo.employeeswipedclose123 READONLY )
AS
BEGIN

   MERGE EmployeSwipeDaily_tbl AS Target

   USING @closingemployee AS Source

   ON (Target.empid = Source.empid) and (Target.Date = Source.datetoday)

   WHEN MATCHED THEN 
       BEGIN 
           UPDATE    Target
            SET Target. IsCompleted = N'Y'
             WHERE     (Source.swipePK = Target.Swipepk) AND (Source.empid = Target.empid) AND (Target.Date = Source.datetoday)   

         WHEN NOT MATCHED THEN

       INSERT INTO Target
       (empid, Swipin, SwipeOut, Date, Duration, deviceid, InStatus, Outstatus, Invalue, OutValue, IsCompleted, CompletedDate)
        VALUES     (@empid, CONVERT(DATETIME, ' 00:00:00', 102), CONVERT(DATETIME, ' 00:00:00', 102),@datetoday, CONVERT(DATETIME, 
                      ' 00:00:00', 102), 0, N'A', N'A', 0, 0, N'Y',(select GETDATE()) )

END


GO

but now what I want is inside the stored procedure I want to loop the Datatable and check a condition

eg like this

for(int i=0 ;i<dt.count;i++)
{
   if(dt.rows[i][swipepk]==0)
   {
       insert into employe swipe tbl()
   }
   else 
   {
       update employee tbl
   }
}

Can anyone suggest a better solution to loop a datatable in a stored procedure?

Answer 1

Since you’re on SQL Server 2008 – this is exactly the scenario for using the MERGE statement! No looping or anything needed – just a single MERGE statement will do!

CREATE PROCEDURE dbo.CloseAttendance (@closingemployee dbo.Employeedata READONLY)
BEGIN
   -- this is the target of your MERGE - where the data is supposed to go
   MERGE dbo.Employees AS Target
   -- this is the source where the data to be merged comes from
   USING @closingemployee AS Source
   -- set up a "join" condition for those two sets of data
   ON Target.empid = Source.empid
   -- now define what to do when that JOIN condition matches
   WHEN MATCHED THEN 
       UPDATE 
          SET Target.SomeColumn = Source.Swipepk  --- or WHATEVER you need to update here!
   -- now define what to do when that JOIN condition DOES NOT match (e.g. new employee)
   WHEN NOT MATCHED THEN
      INSERT(EmpId, CategoryName, Swipepk)
      VALUES(Source.EmpId, Source.CategoryName, Source.Swipepk) ;
END

Of course, you can also do other things – and you can define more matching/non-matching criteria, if needed.

This MERGE statement is run once and does all the work in a single pass – no looping, no RBAR (row-by-agonizing-row) processing – nothing of that sort. One nice, fast, set-based statement and you’re done!

Update: from your updated question, I see you have three major errors in your MERGE statement:

 WHEN MATCHED THEN 
    BEGIN                                 <=== ERROR #1 : you CANNOT have a BEGIN here!
        UPDATE Target
        SET Target.IsCompleted = N'Y'
        WHERE (Source.swipePK = Target.Swipepk)  <=== ERROR #2 : you CANNOT have 
          AND (Source.empid = Target.empid)                      additional WHERE 
          AND (Target.Date = Source.datetoday)                   clause on the UPDATE

WHEN NOT MATCHED THEN
   INSERT INTO Target              <=== ERROR #3: you CANNOT define a INSERT INTO ....
                                      the "INTO" table is already a given by the MERGE
   (empid, Swipin, SwipeOut, Date, Duration, deviceid, InStatus, Outstatus, Invalue, OutValue, IsCompleted, CompletedDate)
    VALUES     (@empid, CONVERT(DATETIME, ' 00:00:00', 102), CONVERT(DATETIME, ' 00:00:00', 102),@datetoday, CONVERT(DATETIME, 
                  ' 00:00:00', 102), 0, N'A', N'A', 0, 0, N'Y',(select GETDATE()) )