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From sube singh <sube.si...@gmail.com>
Subject Re: Use of If control statement in row level trigger
Date Fri, 12 Aug 2005 08:59:39 GMT
Hello,
 Thanks for prompt reply. I have tried following query 
  
*Create trigger APP.TRU_A_STUDENT after update on APP.STUDENT Referencing 
old as oldRow new as newRow For each Row MODE DB2SQL Insert Into 
APP.REP_SHADOW_STUDENT ( Rep_common_id, Rep_operationType, Rep_status, 
ROLLNO , NAME , PAY , CLS , rep_old_ROLLNO , Rep_server_name , 
Rep_PK_Changed ) Values ((Select max(Rep_cid) from Rep_LogTable) , 'U' , 'A' 
, newRow.ROLLNO , newRow.NAME , newRow.PAY , newRow.CLS , oldRow.ROLLNO , 
'sube_3001',(CASE WHEN new.ROLLNO!=old.ROWNO THEN 'Y' ELSE null END))*

It give the following error message : 

ERROR 42X04: Column 'NEW.ROLLNO' is not in any table in the FROM list or it 
appears within a join specification and is outside the scope of the join 
specification or it appears in a HAVING clause and is not in the GROUP BY 
list. If this is a CREATE or ALTER TABLE statement then 'NEW.ROLLNO' is not 
a column in the target table.

 Thanks and Regards,

Sube Singh

 ** 


 On 8/12/05, Ali Demir <demir4@yahoo.com> wrote: 
> 
> There is no such thing as declare variable. Instead you can use something 
> like this instead of pkchanged inside your insert statement:
> 
> (CASE WHEN new.ROLLNO<>old.ROWNO THEN 'Y' ELSE 'N' END)
> 
> Try this to get an idea about how it works:
> 
> SELECT (CASE WHEN 1<>0 THEN 'Y' ELSE 'N' END) as COL1 FROM (VALUES(1)) as 
> t
> 
> Also, there is no begin-end around trigger body. You need to have single 
> statement inside one trigger. You can have multiple triggers if you need 
> multiple statements.
> 
> Regards,
> Suavi 
> 
> 
> At 12:08 AM 8/12/2005, you wrote:
> 
> Hi,
> 
> I would like to insert the value of pk_changed into the table 
> student if old and new primary key value is not same. Plz see the 
> following statement
> 
> Create trigger APP.TRU_A_STUDENT
> after update on APP.STUDENT
> Referencing old as oldRow new as newRow For each Row MODE DB2SQL
> *delclare pkchanged char(1);
> begin
> if(newRow.ROLLNO!=oldRow.ROLLNO!= ) then
> pkchanged ='Y' ;
> end if;
> end;*
> *
> *Insert Into APP.SHADOW_STUDENT(common_id, operationType, status,
> ROLLNO , NAME , PAY , CLS , old_ROLLNO , server_name ) Values ((Select
> max(cid) from TempTable,pk_change_cols) , 'U' , 'A' , newRow.ROLLNO , 
> newRow.NAME ,
> newRow.PAY , newRow.CLS , oldRow.ROLLNO , 'sube_3001',*pkchanged* )
> 
> I hope that you will reply me as soon as possible 
> 
> Thanks ans Regards,
> 
> Sube Singh
> 
> 
> 
> 
> On 8/12/05, Ali Demir <demir4@yahoo.com> wrote:
> > Where do you use the pkchanged that you are setting to 'Y'? In some 
> cases,
> > you can use CASE statement inside INSERT etc too if you want. I am 
> assuming 
> > you are trying to execute the triggered insert ONLY IF the Primary Key 
> value
> > of the new row is different than the old row and the PK column is 
> ROLLNO.
> > 
> > In general, it could be like this (@see bold): 
> > 
> > Create trigger APP.TRU_A_STUDENT 
> > after update on APP.STUDENT 
> > Referencing old as oldRow new as newRow For each Row MODE DB2SQL 
> > Insert Into APP.SHADOW_STUDENT(common_id, operationType, status, 
> > ROLLNO , NAME , PAY , CLS , old_ROLLNO , server_name ) SELECT * FROM 
> (Values
> > ((Select
> > max(cid) from TempTable) , 'U' , 'A' , newRow.ROLLNO , newRow.NAME ,
> > newRow.PAY , newRow.CLS , oldRow.ROLLNO , 'sube_3001')) as t WHERE
> > (newRow.ROLLNO<>oldRow.ROLLNO)
> > 
> > I don't have your db schema, so I did not test, but you get the idea: 
> When
> > you append the where clause, the select returns nothing, and you insert 
> > nothing if PK has not changed.
> > 
> > VALUES syntax when used inside a FROM clause is as follows:
> > 
> > select * from (VALUES(1)) as temp
> > 
> > Excuse my html formatting if it causes trouble. 
> > 
> > Regards,
> > Suavi
> > 
> > 
> > At 11:27 PM 8/11/2005, you wrote:
> > Hi,
> > 
> > Lot of thanks for your reply. I have the following trigger. 
> > 
> > 
> > Create trigger APP.TRU_A_STUDENT 
> > after update on APP.STUDENT 
> > Referencing old as oldRow new as newRow For each Row MODE DB2SQL 
> > Insert Into APP.SHADOW_STUDENT(common_id, operationType, status,
> > ROLLNO , NAME , PAY , CLS , old_ROLLNO , server_name ) Values ((Select 
> > max(cid) from TempTable) , 'U' , 'A' , newRow.ROLLNO , newRow.NAME ,
> > newRow.PAY , newRow.CLS , oldRow.ROLLNO , 'sube_3001')
> > 
> > 
> > I would like to add the following statement in trigger before 
> > execution of insert statement :
> > 
> > delclare pkchanged char(1);
> > begin 
> > if(newRow.ROLLNO!=oldRow.ROLLNO!=) then 
> > pkchanged ='Y' ;
> > end if;
> > end;
> > 
> > Please reply me I am waiting. 
> > 
> > Thanks and Regrds,
> > Sube Singh
> > 
> > 
> > 
> > 
> > On 8/12/05, Ali Demir <demir4@yahoo.com> wrote:
> > > Conditionally firing the trigger is not supported yet if i remember 
> > correct,
> > > but you can carry the IF condition into the where clause.
> > > 
> > > Example:
> > > 
> > > create trigger S.TRIGNAME
> > > after update of COL1 on S.T1
> > > referencing NEW as N OLD as O 
> > > for each row mode db2sql 
> > > insert into S.T2(COLN) 
> > > select COLX 
> > > from S.T3 
> > > where (not N.COL1=O.COL1);
> > > 
> > > 
> > > This will insert nothing if the condition (not N.COL1=O.COL1) 
> evaluates to
> > > FALSE. [may need to check for NULLs separately if cols are nullable in
> > these
> > > things] 
> > > 
> > > It will feel like trigger did not fire.
> > > 
> > > Regards,
> > > Suavi
> > > 
> > > 
> > > 
> > > At 10:03 PM 8/11/2005, you wrote:
> > > Hi, 
> > > 
> > > Can any one help? I would like to use the IF control statement in row
> > level 
> > > trigger. I do not find any detail related to it in manual and on web
> > > site.If any
> > > have Idea about it please post me a example.
> > > 
> > > Waiting for your reply.
> > > 
> > > Thanks and Regrds,
> > > 
> > > Sube Singh
> 
>

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