How to avoid duplicate record while inserting data using user defined table type in SQL Server

Question

I am trying to insert entire model in database using my .net application. I am using a user-defined table type.

This is my procedure and user-defined table; I am using SQL Server 2012.

CREATE TYPE [dbo].[TmpAccessRequest] AS TABLE
(
    [RequestId] [int] NULL,
    [RequesterID] [int] NULL,
    [RequestType] [int] NULL,
    [NextApprover] [int] NULL,
    [RequestStatus] [varchar](100) NULL,
    [Delegation] [int] NULL,
    [CreatedOn] [date] NULL,
    [CreatedBy] [varchar](100) NULL,
    [Description] [varchar](max) NULL,
    [IsSepecialRequest] [bit] NULL,
    [DelegationDetailID] [int] NULL,
    [IsActive] [bit] NULL,
    [IsDeleted] [bit] NULL,
    [ModifiedOn] [date] NULL
)
GO

CREATE PROCEDURE [dbo].[proc_SaveAccessRequest] 
   (@TmpAR TmpAccessRequest READONLY,
    @IsUAMSRequest BIT,
    @RequestID INT OUTPUT) 
AS  
BEGIN
    INSERT INTO tblRequests (RequesterID, RequestType, NextApprover, RequestStatus,
                             Delegation, CreatedOn, CreatedBy, Description,
                             IsSepecialRequest, DelegationDetailID, IsActive, IsDeleted, ModifiedOn)
        SELECT
            RequesterID, RequestType, NextApprover, RequestStatus,
            Delegation, CreatedOn, CreatedBy, Description,
            IsSepecialRequest, DelegationDetailID, IsActive, IsDeleted, ModifiedOn
        FROM
            @TmpAR  

    SET @RequestID = SCOPE_IDENTITY()

    --SET @RequestID=IDENT_CURRENT('tblRequests') 
    SELECT @RequestID
END

I want to check if duplicate data should not insert at the same time. So how can I do that with user-defined table type ?

Answer 1

Please find the changes done to your script to avoid inserting duplicate record. So i considered two columns data should be unique to avoid duplication for user understanding purpose

 CREATE PROCEDURE [dbo].[proc_SaveAccessRequest] 
(
  @TmpAR TmpAccessRequest READONLY,
  @IsUAMSRequest bit,
  @RequestID int OUTPUT
) 
AS  
BEGIN

     Insert into tblRequests
    (
       RequesterID
      ,RequestType
      ,NextApprover
      ,RequestStatus
      ,Delegation
      ,CreatedOn
      ,CreatedBy
      ,[Description]
      ,IsSepecialRequest
      ,DelegationDetailID
      ,IsActive
      ,IsDeleted
      ,ModifiedOn
    )
    SELECT
       RequesterID
      ,RequestType
      ,NextApprover
      ,RequestStatus
      ,Delegation
      ,CreatedOn
      ,CreatedBy
      ,Description
      ,IsSepecialRequest
      ,DelegationDetailID
      ,IsActive
      ,IsDeleted
      ,ModifiedOn
     FROM @TmpAR  
     WHERE NOT EXISTS ( SELECT 1 
                        FROM tblRequests i
                        INNER JOIN @TmpAR o  
                            ON i.RequesterID = o.RequesterID
                         AND i.RequestType = o.RequestType 
                         AND i.NextApprover = o.NextApprover)

     SELECT @RequestID = SCOPE_IDENTITY()

     SELECT @RequestID
END