急求触发器解答

我刚开始用触发器，请向大家请教一个问题：我写了一个触发器如下：
CREATE TRIGGER [forbidToDeleteCompany] ON [dbo].[Company]
FOR DELETE
AS
begin

declare @tableName varchar(255)
declare @fieldName varchar(255)
declare @tcount int
DECLARE tableFieldCursor CURSOR FOR
select t.[name] as tableName,f.[name] as fieldName
from sysobjects as t
inner join syscolumns as f
on t.id = f.id
where t.type='U' and lower(f.[name]) like '%companycode'

OPEN tableFieldCursor
FETCH NEXT FROM tableFieldCursor
INTO @tableName, @fieldName
WHILE @@FETCH_STATUS = 0
BEGIN
exec('select @tcount = count(d.code) from deleted as d inner join '+ @tableName +' as p on d.code=p.' + @fieldName)
if @tcount >0
RAISERROR ('记录在使用中不能删除！', 16, 1)
rollback transaction
goto quit

FETCH NEXT FROM tableFieldCursor
INTO @tableName, @fieldName

END

quit:
CLOSE tableFieldCursor
DEALLOCATE tableFieldCursor

end

但是在删除记录时，触发器出错，提示“必须声明变量@tcount”，经查是exec语句出错，但不知道该如何写才对，请大家不吝赐教。