sql 插入触发器后的MS SQL

Posted 2021-05-13

-- After Insert trigger
ALTER TRIGGER [Person].[ContactTypeTrigger]
      ON [Person].[ContactType] 
AFTER Insert, Update
AS 
   IF ('Batman' = (SELECT  I.Name FROM inserted I))
        BEGIN
	  RAISERROR('You can`t add Batman.',16,1);
	  ROLLBACK TRANSACTION;
	END

   IF Update(Name)
     SELECT  'Name was modified from ' 
           + D.Name 
           + ' to '
           + I.Name 
      FROM Inserted I
	  JOIN Deleted D
	  ON I.ContactTypeID = D.ContactTypeID;;
   
GO

-- Execution 1 (Success)
Update Person.ContactType 
   SET Name = 'Contractor' WHERE Name = 'Sales Manager'
-- [Output]
-- Name was modified from Sales Manager to Contractor

-- Execution 2 (Fails)
Update Person.ContactType 
   SET Name = 'Batman' WHERE Name = 'Contractor'
-- [Output]
-- Msg 50000,...
-- You can`t add Batman.