请问我的表这样设计 是否合理 有什么弊端
if   exists   (select   *   from   dbo.sysobjects   where   id   =   object_id(N '[dbo].[BM_Person] ')   and   OBJECTPROPERTY(id,   N 'IsUserTable ')   =   1)
drop   table   [dbo].[BM_Person]
GO

if   exists   (select   *   from   dbo.sysobjects   where   id   =   object_id(N '[dbo].[BM] ')   and   OBJECTPROPERTY(id,   N 'IsUserTable ')   =   1)
drop   table   [dbo].[BM]
GO

if   exists   (select   *   from   dbo.sysobjects   where   id   =   object_id(N '[dbo].[BM_zhiwu] ')   and   OBJECTPROPERTY(id,   N 'IsUserTable ')   =   1)
drop   table   [dbo].[BM_zhiwu]
GO

if   exists   (select   *   from   dbo.sysobjects   where   id   =   object_id(N '[dbo].[BM_yuangong] ')   and   OBJECTPROPERTY(id,   N 'IsUserTable ')   =   1)
drop   table   [dbo].[BM_yuangong]
GO

CREATE   TABLE   [dbo].[BM_Person]   (
[bm_id]   [int]   NULL   ,
[person_id]   [int]   NULL   ,
[zhiwu_id]   [int]   NULL  
)   ON   [PRIMARY]
GO
CREATE   TABLE   [dbo].[BM]   (
[BM_id]   [int]   IDENTITY   (1,   1)   NOT   NULL   ,
[BM_name]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[BM_miaoshu]   [varchar]   (8000)   COLLATE   Chinese_PRC_CI_AS   NULL  
)   ON   [PRIMARY]
GO

CREATE   TABLE   [dbo].[BM_zhiwu]   (
[zhiwu_id]   [int]   IDENTITY   (1,   1)   NOT   NULL   ,
[zhiwu_name]   [varchar]   (500)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[zhiwu_bm_id]   [int]   NULL  
)   ON   [PRIMARY]
GO

CREATE   TABLE   [dbo].[BM_yuangong]   (
[Person_id]   [int]   IDENTITY   (1,   1)   NOT   NULL   ,
[Person_zhuangtai]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[Person_daima]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[Person_xingming]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[Person_xingbie]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[Person_jiguan]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[Person_chusheng]   [datetime]   NULL   ,
[Person_ruzhi]   [datetime]   NULL   ,
[Person_xueli]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[Person_xuexiao]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[Person_zhuanye]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[Person_dianhua]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[Person_fenji]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[Person_shouji]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[Person_dizhi]   [varchar]   (50)   COLLATE   Chinese_PRC_CI_AS   NULL   ,