Sybase Update Trigger - Verifique múltiples filas para actualizar

Question

Estoy escribiendo un disparador en una base de datos Sybase ASE, que dispara en una actualización y compara el valor antes y después de la actualización.Hago esto para verificar si la actualización ha cambiado realmente los datos.Si este es el caso, agrega una fila a una tabla de monitoreo.Desafortunadamente, el disparador solo funciona si el comando de actualización solo afecta a 1 fila.Si está afectando más de una fila, obtengo este error:

Msg 512, Level 16, State 5:
Server 'myserver', Procedure 'myproc', Line 2:
Subquery returned more than 1 value.  This is illegal when the subquery follows =, !=, <, <= , >, >=, or when the subquery is used as an expression.

Mi proc se ve así:

create trigger mytrigger on mytable for update as

set nocount on

/* now do the insert if colum was updated  */
if update(col_a) and (select col_a from inserted) not in (select col_a from deleted) 
begin
    insert into monitoring_table (login,tablename,field,action,pstamp) 
        select suser_name(),'mytable','col_a','U',getdate() from inserted
end
/* now do the insert if colum was updated  */
if update(col_b) and (select col_b from inserted) not in (select col_b from deleted) 
begin
    insert into monitoring_table (login,tablename,field,action,pstamp) 
        select suser_name(),'mytable','col_b','U',getdate() from inserted
end
go

¿Alguna idea de cómo puedo conseguir en este problema de actualización múltiple dentro de mi gatillo?

Answer 1

Si el error está en desencadenante, entonces el siguiente debe funcionar: en lugar de:

if update(col_a) and (select col_a from inserted) not in (select col_a from deleted)

Uso

if update(col_a) and exists (select col_a from inserted where col_a not in (select col_a from deleted))

Answer 2

Esto debería funcionar:

create trigger mytrigger on mytable for update as

set nocount on

/* now do the insert if colum was updated  */
if update(col_a) and (select col_a from inserted where col_a not in (select col_a from deleted) 
begin
    insert into monitoring_table (login,tablename,field,action,pstamp) 
        select suser_name(),'mytable','col_a','U',getdate() from inserted
end
/* now do the insert if colum was updated  */
if update(col_b) and (select col_b from inserted where col_b not in (select col_b from deleted) 
begin
    insert into monitoring_table (login,tablename,field,action,pstamp) 
        select suser_name(),'mytable','col_b','U',getdate() from inserted
end
go