哪错了?

alter   table   D_SchEduleMain   alter   column   SchEduleMainStatus   int     default   1
服务器:   消息   156，级别   15，状态   1，行   2
在关键字   'default '   附近有语法错误。

CREATE   TABLE   [D_SchEduleMain]   (
[SEMID]   [int]   IDENTITY   (1,   1)   NOT   NULL   ,
[UID]   [int]   NULL   ,
[SchEduleMainTitle]   [nvarchar]   (100)   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[SchEduleMainMemo]   [ntext]   COLLATE   Chinese_PRC_CI_AS   NULL   ,
[SchEduleMainFirstTime]   [datetime]   NULL   ,
[SchEduleMainLastTime]   [datetime]   NULL   ,
[SchEduleMainImportant]   [int]   NULL   ,
[SchEduleMainType]   [int]   NULL   ,
[SchEduleMainStatus]   [int]   NULL   CONSTRAINT   [DF__D_SchEdul__SchEd__239E4DCF]   DEFAULT   (0),
  PRIMARY   KEY     CLUSTERED  
(
[SEMID]
)     ON   [PRIMARY]   ,
  FOREIGN   KEY  
(
[SchEduleMainImportant]
)   REFERENCES   [D_SchEduleImportant]   (
[SEIID]
),
  FOREIGN   KEY  
(
[SchEduleMainType]
)   REFERENCES   [D_SchEduleSort]   (
[SEID]
),
  FOREIGN   KEY  
(
[UID]
)   REFERENCES   [D_admin]   (
[adminID]
)
)   ON   [PRIMARY]   TEXTIMAGE_ON   [PRIMARY]
GO




------解决方案--------------------
alter table D_SchEduleMain
add constraint AddDefault default(1) for SchEduleMainStatus with values
------解决方案--------------------
不能直接修改表的默认值，必须先删除默认值约束，然后添加默认值约束。