Performing UPDATE with AFTER UPDATE trigger SQL Server 2008 R2

Question

I have a table with 1000+ records in SQL Server 2008 R2. There is a SharePoint 2010 interface where users can update the rows of this table in real time, and there is one field (CLASS) that should be calculated upon update of one or two columns (COUNTRY_REASON or/and VENDOR_REASON).

I am thinking about creating an AFTER UPDATE trigger upon update, although I wonder if it won't get in a loop of some kind?

Is there a better way to perform this update than using a trigger? What is your opinion/advice?

CREATE TRIGGER [dbo].[TRG_NOSSCE_UPDATE_CLASS] 
ON [TO_BDB].[dbo].[to_bdb_nossce_comm_act] 
after UPDATE 
AS 
  BEGIN 
      UPDATE [TO_BDB].[dbo].[to_bdb_nossce_comm_act] 
      SET    class = CASE 
                       WHEN ( country_reason = '' OR country_reason IS NULL ) 
                            AND ( vendor_reason = '' OR vendor_reason IS NULL ) 
                       THEN 'NOT CLASSIFIED' 
                       WHEN country_reason = 'Vendor_Issue' 
                            AND ( vendor_reason = '' OR vendor_reason IS NULL ) 
                       THEN 'SITE ISSUE' 
                       WHEN country_reason = 'Vendor_Issue' 
                             OR country_reason = '' 
                             OR country_reason IS NULL 
                      THEN ( 
                         CASE 
                           WHEN vendor_reason IN ( 'Site Product Quality', 'Site QA Release' ) 
                           THEN 'SITE QUALITY' 
                           WHEN vendor_reason = 'Customer Order Management' 
                           THEN 'CPO SCM' 
                         WHEN vendor_reason LIKE 'Other%' THEN 'OTHER REASON' 
                         ELSE 'SITE SCM' 
                         END 
                       ) 
                       ELSE ( 
                         CASE 
                                WHEN country_reason IN ( 'Local Product Quality', 
                                                         'Local QA Release' 
                                                       ) 
                                THEN 'CPO QUALITY' 
                                WHEN country_reason IN ( 'Customs Clearance', 
                                                         'Transport Damage', 
                                                         'Transport Issue' ) 
                                THEN 'TRANSIT' 
                                WHEN country_reason IN ( 
                                     'Artwork', 'Complaince Checks', 
                                     'Registration', 
                                     'Safety Label Changes' ) 
                                THEN 'CPO LCM' 
                                WHEN country_reason = 'Vendor_Issue' 
                                THEN '' 
                                WHEN country_reason LIKE 'Other%' 
                                THEN 'OTHER REASON' 
                                ELSE 'CPO SCM' 
                          END 
                        ) 
                     END 
      WHERE  class = '' 
              OR class IS NULL 
                 AND Len(comment) > 0 
  END 

go 

Answer 1

You use "INSTEAD OF INSERT,UPDATE" and avoid the update with a single insert

Articles:

• Using INSTEAD OF Triggers - MSDN
• How to Use INSTEAD OF Trigger - Pinal Dave

Try this ! add other columns where i have commented

create  TRIGGER TRG_NOSSCE_UPDATE_CLASS
ON [dbo].[to_bdb_nossce_comm_act]
instead OF UPDATE
AS
  BEGIN
      UPDATE a
      SET    a.class = CASE
                         WHEN ( a.country_reason = ''
                                 OR a.country_reason IS NULL )
                              AND ( a.vendor_reason = ''
                                     OR a.vendor_reason IS NULL ) THEN 'NOT CLASSIFIED'
                         WHEN a.country_reason = 'Vendor_Issue'
                              AND ( a.vendor_reason = ''
                                     OR a.vendor_reason IS NULL ) THEN 'SITE ISSUE'
                         WHEN a.country_reason = 'Vendor_Issue'
                               OR a.country_reason = ''
                               OR a.country_reason IS NULL THEN ( CASE
                                                                  WHEN a.vendor_reason IN ( 'Site Product Quality', 'Site QA Release' ) THEN 'SITE QUALITY'
                                                                  WHEN a.vendor_reason = 'Customer Order Management' THEN 'CPO SCM'
                                                                  WHEN a.vendor_reason LIKE 'Other%' THEN 'OTHER REASON'
                                                                  ELSE 'SITE SCM'
                                                                END )
                         ELSE ( CASE
                                  WHEN a.country_reason IN ( 'Local Product Quality', 'Local QA Release' ) THEN 'CPO QUALITY'
                                  WHEN a.country_reason IN ( 'Customs Clearance', 'Transport Damage', 'Transport Issue' ) THEN 'TRANSIT'
                                  WHEN a.country_reason IN ( 'Artwork', 'Complaince Checks', 'Registration', 'Safety Label Changes' ) THEN 'CPO LCM'
                                  WHEN a.country_reason = 'Vendor_Issue' THEN ''
                                  WHEN a.country_reason LIKE 'Other%' THEN 'OTHER REASON'
                                  ELSE 'CPO SCM'
                                END )
                       END
      --,
      --a.column1=b.column1,
      --a.othercolumns=b.othercolumns
      FROM   [dbo].[to_bdb_nossce_comm_act] a,
             inserted b
      WHERE  a.class = ''
              OR a.class IS NULL
                 AND Len(a.comment) > 0
  END

go 

Imagining you use a cursor in your SP and have @class,@countryreason and @vendorreason as cursor variables, we can do as below

cursor loop....start
SET   @class = CASE
                         WHEN ( @country_reason = ''
                                 OR @country_reason IS NULL )
                              AND ( vendor_reason = ''
                                     OR @vendor_reason IS NULL ) THEN 'NOT CLASSIFIED'
                         WHEN @country_reason = 'Vendor_Issue'
                              AND ( @vendor_reason = ''
                                     OR @vendor_reason IS NULL ) THEN 'SITE ISSUE'
                         WHEN @country_reason = 'Vendor_Issue'
                               OR @country_reason = ''
                               OR @country_reason IS NULL THEN ( CASE
                                                                  WHEN @vendor_reason IN ( 'Site Product Quality', 'Site QA Release' ) THEN 'SITE QUALITY'
                                                                  WHEN @vendor_reason = 'Customer Order Management' THEN 'CPO SCM'
                                                                  WHEN @vendor_reason LIKE 'Other%' THEN 'OTHER REASON'
                                                                  ELSE 'SITE SCM'
                                                                END )
                         ELSE ( CASE
                                  WHEN @country_reason IN ( 'Local Product Quality', 'Local QA Release' ) THEN 'CPO QUALITY'
                                  WHEN @country_reason IN ( 'Customs Clearance', 'Transport Damage', 'Transport Issue' ) THEN 'TRANSIT'
                                  WHEN @country_reason IN ( 'Artwork', 'Complaince Checks', 'Registration', 'Safety Label Changes' ) THEN 'CPO LCM'
                                  WHEN @country_reason = 'Vendor_Issue' THEN ''
                                  WHEN @country_reason LIKE 'Other%' THEN 'OTHER REASON'
                                  ELSE 'CPO SCM'
                                END )
                       END

update table set other columns....,class=@class,.... where...

close cursor loop

SP can be more clear only if u share a piece or glance of it.