DELETE statement issues within a trigger definition

问题

I have created an insert/update trigger that is designed to update information in a different table based on the data being inserted. The last thing the trigger does (or is supposed to do) is remove all data from a target table with conditions that may have changed during the insert portions of the trigger.

Everything appears to be working with the trigger except the final DELETE statement. It is executing the DELETE statement, but not following any of the conditions in the where clause. It simply deletes everything in the table.

I have even tried changing the NOT IN in the where clause to IN, and it still does the same. I have isolated the DELETE statement and tested outside the trigger and it works fine (using the same variables and subqueries).

Am I missing something with the behavior of a trigger?

Here comes the code:

ALTER TRIGGER [dbo].[cust_trgr_profile_attribute] 
ON [dbo].[port_module_instance_setting]      
AFTER INSERT, UPDATE
AS

DECLARE @ModuleId INT=449,
        @MatchGroupModSetting VARCHAR(50) = 'AttributeGroup',
        @FilterGroupModSetting VARCHAR(50) = 'FilterAttributeGroup',
        @MatchAttributes TABLE (attribute_id INT),
        @FilterAttributes TABLE (attribute_id INT)

INSERT INTO @MatchAttributes
  SELECT DISTINCT camatch.attribute_id 
  FROM inserted I
  JOIN core_attribute camatch ON I.value = CONVERT(VARCHAR(10), camatch.attribute_group_id)
  JOIN port_module_instance pmi ON I.module_instance_id = pmi.module_instance_id
       AND pmi.module_id=@ModuleId
  WHERE I.name like @MatchGroupModSetting+'_'

INSERT INTO @FilterAttributes
  SELECT DISTINCT cafilter.attribute_id 
  FROM inserted I
  JOIN core_attribute cafilter ON I.value = CONVERT(VARCHAR(10), cafilter.attribute_group_id)
  JOIN port_module_instance pmi ON I.module_instance_id = pmi.module_instance_id
       AND pmi.module_id=@ModuleId
  WHERE I.name=@FilterGroupModSetting

IF ((SELECT COUNT(*) FROM @MatchAttributes) > 0 OR (SELECT COUNT(*) FROM @FilterAttributes) > 0)
BEGIN
    IF (SELECT COUNT(*) FROM @MatchAttributes) > 0
    BEGIN
        UPDATE cpa 
           SET cpa.[required]=0
          FROM cust_profile_attribute cpa
          JOIN @MatchAttributes ma ON cpa.attribute_id = ma.attribute_id
    END

    IF (SELECT COUNT(*) FROM @FilterAttributes) > 0
    BEGIN
        UPDATE cpa 
           SET cpa.[required]=0
          FROM cust_profile_attribute cpa
          JOIN @FilterAttributes fa ON cpa.attribute_id=fa.attribute_id
    END

    DELETE FROM cust_profile_attribute
    WHERE attribute_id NOT IN (SELECT distinct ca.attribute_id 
                               FROM core_attribute ca
                               JOIN port_module_instance_setting inst ON CONVERT(VARCHAR(10),ca.attribute_group_id) = inst.value
                               JOIN port_module_instance modinst ON inst.module_instance_id = modinst.module_instance_id
                                    AND modinst.module_id = @ModuleId
                               WHERE inst.name like @MatchGroupModSetting + '_'
                               OR inst.name like @FilterGroupModSetting)
END

回答1:

I have found a flaw in my fundamental logic of how the trigger works. I have now refined my understanding of what is going on and able to articulate more information for others to help. Rather than try to completely transform the original post, I thought it better to post the new info here.

The basic idea is that the port_module_instance_setting table stores a string in the that represents a setting (in this specific case, the conditions are set so that the value field will always be a number). What I am trying to accomplish is that when the value field is updated in one of these specific "settings", everything in the cust_profile_attribute table that is referenced by the old value gets deleted. In this context, the value field of port_module_instance_setting is a numeric varchar value that directly references the attribute_group_id of core_attribute. Please don't comment on best practices regarding referencing tables using different data types, as I have no control over the actual table structure :) Everything in the trigger functions properly, except the DELETE statement at the end. It isn't doing anything. Any ideas on why it isn't deleting the attributes I want it to?

I have changed the DELETE statement as follows to reference the pre-updated valuefield.

DELETE FROM cust_profile_attribute
WHERE attribute_id IN(SELECT ISNULL(attribute_id,-1) FROM deleted d
                      JOIN core_attribute ca ON ca.attribute_group_id= CONVERT(INT,d.value))

来源：https://stackoverflow.com/questions/11767725/delete-statement-issues-within-a-trigger-definition