MYSQL bir er diagram sorusu

CREATE TRIGGER PreventDuplicateRecords1 
  ON SECRETARY 
  AFTER INSERT 
  AS 
  BEGIN 
  DECLARE @Count1 int 
  DECLARE @Count2 int 
  DECLARE @SSN nvarchar(50) 
  SELECT @SSN=SSN FROM INSERTED 
  SELECT @Count1=count(*) FROM 
  ENGINEER WHERE SSN=@SSN 
  SELECT @Count2=count(*) FROM 
  TECHNICIAN WHERE SSN=@SSN 
  IF @Count1+@Count2>0 
  BEGIN 
  ROLLBACK TRANSACTION 
  END 
  END 
   
   
  GO